ipapwpolicy: Allow execution of plugin in client host.

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

A new test playbook can be found at:

    tests/pwpolicy/test_pwpolicy_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/pwpolicy/test_pwpolicy.yml

@@ -1,6 +1,6 @@
 ---
 - name: Test pwpolicy
-  hosts: ipaserver
+  hosts: "{{ ipa_test_host | default('ipaserver') }}"
   become: true
   gather_facts: false
 
@@ -8,23 +8,27 @@
   - name: Ensure maxlife of 90 for global_policy
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       maxlife: 90
 
   - name: Ensure absence of group ops
     ipagroup:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: ops
       state: absent
 
   - name: Ensure absence of pwpolicies for group ops
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: ops
       state: absent
 
   - name: Ensure presence of group ops
     ipagroup:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: ops
       state: present
     register: result
@@ -33,6 +37,7 @@
   - name: Ensure presence of pwpolicies for group ops
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: ops
       minlife: 7
       maxlife: 49
@@ -49,6 +54,7 @@
   - name: Ensure presence of pwpolicies for group ops again
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: ops
       minlife: 7
       maxlife: 49
@@ -65,6 +71,7 @@
   - name: Ensure maxlife of 49 for global_policy
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       maxlife: 49
     register: result
     failed_when: not result.changed or result.failed
@@ -72,6 +79,7 @@
   - name: Ensure maxlife of 49 for global_policy again
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       maxlife: 49
     register: result
     failed_when: result.changed or result.failed
@@ -79,6 +87,7 @@
   - name: Ensure absence of pwpoliciy global_policy will fail
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       state: absent
     register: result
     failed_when: not result.failed or "'global_policy' can not be made absent." not in result.msg
@@ -86,6 +95,7 @@
   - name: Ensure absence of pwpolicies for group ops
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: ops
       state: absent
     register: result
@@ -94,6 +104,7 @@
   - name: Ensure maxlife of 90 for global_policy
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       maxlife: 90
     register: result
     failed_when: not result.changed or result.failed
@@ -101,6 +112,7 @@
   - name: Ensure absence of pwpolicies for group ops
     ipapwpolicy:
       ipaadmin_password: SomeADMINpassword
+      ipaapi_context: "{{ ipa_context | default(omit) }}"
       name: ops
       state: absent
     register: result