Backport improvements to role_assignment

- Refactor module

Change-Id: I09258e18d50acb57501ea1b47d9422dad857607e
(cherry picked from commit 8d5195fdf2)

ci/roles/role_assignment/tasks/main.yml

@@ -0,0 +1,47 @@
+---
+- name: Create project
+  openstack.cloud.project:
+     cloud: "{{ cloud }}"
+     state: present
+     name: ansible_project
+     description: dummy description
+     domain_id: default
+     enabled: True
+  register: project
+
+- name: Grant an admin role on the user admin in the project ansible_project
+  openstack.cloud.role_assignment:
+    cloud: "{{ cloud }}"
+    domain: default
+    project: ansible_project
+    role: admin
+    user: admin
+
+- name: Grant an admin role on the user admin in the project ansible_project again
+  openstack.cloud.role_assignment:
+    cloud: "{{ cloud }}"
+    domain: default
+    project: ansible_project
+    role: admin
+    user: admin
+  register: grant_again
+
+- name: Ensure grant again doesn't change anything
+  assert:
+    that:
+      - not grant_again.changed
+
+- name: Revoke the admin role on the user admin in the project ansible_project
+  openstack.cloud.role_assignment:
+    cloud: "{{ cloud }}"
+    domain: default
+    project: ansible_project
+    role: admin
+    state: absent
+    user: admin
+
+- name: Delete project
+  openstack.cloud.project:
+     cloud: "{{ cloud }}"
+     state: absent
+     name: ansible_project

ci/run-collection.yml

@@ -51,6 +51,7 @@
     - { role: port, tags: port }
     - { role: project, tags: project }
     - { role: recordset, tags: recordset }
+    - { role: role_assignment, tags: role_assignment }
     - { role: router, tags: router }
     - { role: security_group, tags: security_group }
     - { role: server, tags: server }