Replace deprecated include with import_tasks and include_tasks

As the old way to include tasks is deprecated, replace static include
statements with import_tasks and dynamic ones with include_tasks.

Increaded the required ansible version to 2.5.0 to make sure that
include_tasks and import_tasks is working as expected.

Fixes issue #38

roles/ipaserver/tasks/install.yml

@@ -22,8 +22,7 @@
   when: ipaserver_setup_adtrust | bool
 
 - name: Install - Include Python2/3 import test
-  include: "{{role_path}}/tasks/python_2_3_test.yml"
-  static: yes
+  import_tasks: "{{role_path}}/tasks/python_2_3_test.yml"
 
 - name: Install - Server installation test
   ipaserver_test:

roles/ipaserver/tasks/main.yml

@@ -10,9 +10,9 @@
     - "vars/default.yml"
 
 - name: Install IPA server
-  include: tasks/install.yml
+  include_tasks: tasks/install.yml
   when: state|default('present') == 'present'
 
 - name: Uninstall IPA server
-  include: tasks/uninstall.yml
+  include_tasks: tasks/uninstall.yml
   when: state|default('present') == 'absent'

roles/ipaserver/tasks/uninstall.yml

@@ -2,8 +2,7 @@
 # tasks to uninstall IPA server
 
 #- name: Uninstall - Include Python2/3 import test
-#  include: "{{role_path}}/tasks/python_2_3_test.yml"
-#  static: yes
+#  import: "{{role_path}}/tasks/python_2_3_test.yml"
 
 - name: Uninstall - Uninstall IPA server
   command: >