ipauser: Allow execution of plugin in client host.

Update user README file and add tests for executing plugin with
`ipaapi_context` set to `client`.

A new test playbook can be found at:

    tests/user/test_user_client_context.yml

The new test file can be executed in a FreeIPA client host that is
not a server. In this case, it should be defined in the `ipaclients`
group, in the inventory file.

tests/user/test_user.yml

@@ -1,6 +1,6 @@
 ---
 - name: Test user
-  hosts: ipaserver
+  hosts: "{{ ipa_test_host | default('ipaserver') }}"
   become: true
   gather_facts: false
 
@@ -8,12 +8,14 @@
   - name: Remove test users
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: manager1,manager2,manager3,pinky,pinky2
       state: absent
 
   - name: User manager1 present
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: manager1
       first: Manager
       last: One
@@ -23,6 +25,7 @@
   - name: User manager2 present
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: manager2
       first: Manager
       last: One
@@ -32,6 +35,7 @@
   - name: User manager3 present
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: manager3
       first: Manager
       last: One
@@ -41,6 +45,7 @@
   - name: User pinky present
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       uid: 10001
       gid: 100
@@ -84,6 +89,7 @@
   - name: User pinky present with changed settings
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       first: pinky
       last: Acme
@@ -98,6 +104,7 @@
   - name: User pinky add manager manager1
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       manager: manager1
       action: member
@@ -107,6 +114,7 @@
   - name: User pinky add manager manager1 again
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       manager: manager1
       action: member
@@ -116,6 +124,7 @@
   - name: User pinky add manager manager2, manager3
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       manager: manager2,manager3
       action: member
@@ -125,6 +134,7 @@
   - name: User pinky add manager manager2, manager3 again
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       manager: manager2,manager3
       action: member
@@ -134,6 +144,7 @@
   - name: User pinky remove manager manager1
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       manager: manager1
       action: member
@@ -144,6 +155,7 @@
   - name: User pinky remove manager manager1 again
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       manager: manager1
       action: member
@@ -154,6 +166,7 @@
   - name: User pinky add principal pa
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       principal: pa
       action: member
@@ -163,6 +176,7 @@
   - name: User pinky add principal pa again
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       principal: pa
       action: member
@@ -172,6 +186,7 @@
   - name: User pinky add principal pa1
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       principal: pa1
       action: member
@@ -181,6 +196,7 @@
   - name: User pinky remove principal pa1
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       principal: pa1
       action: member
@@ -191,6 +207,7 @@
   - name: User pinky remove principal pa1 again
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       principal: pa1
       action: member
@@ -201,6 +218,7 @@
   - name: User pinky remove principal pa
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       principal: pa
       action: member
@@ -211,6 +229,7 @@
   - name: User pinky remove principal non-existing pa2
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       principal: pa2
       action: member
@@ -221,6 +240,7 @@
   - name: User pinky absent and preserved
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       preserve: yes
       state: absent
@@ -230,6 +250,7 @@
   - name: User pinky undeleted (preserved before)
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       state: undeleted
     register: result
@@ -238,6 +259,7 @@
   - name: Users pinky disabled
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       state: disabled
     register: result
@@ -246,6 +268,7 @@
   - name: User pinky enabled
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: pinky
       state: enabled
     register: result
@@ -254,5 +277,6 @@
   - name: Remove test users
     ipauser:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: manager1,manager2,manager3,pinky,pinky2
       state: absent