rhsm_repository: deprecate "state=present" and "state=absent" (#6673)

"state=present" is broken, and acts like "disabled"; also, the
subscription repositories cannot be really "added" or "removed", which
is what "present" and "absent" would imply, but only enabled or
disabled. Hence, deprecate both these states, slating them for removal
in community.general 10.0.0.

changelogs/fragments/6673-rhsm_repository-deprecate-present-absent.yml

@@ -0,0 +1,8 @@
+deprecated_features:
+- |
+  rhsm_repository - ``state=present`` has not been working as expected for many years,
+  and it seems it was not noticed so far; also, "presence" is not really a valid concept
+  for subscription repositories, which can only be enabled or disabled. Hence, mark the
+  ``present`` and ``absent`` values of the ``state`` option as deprecated, slating them
+  for removal in community.general 10.0.0
+  (https://github.com/ansible-collections/community.general/pull/6673).

plugins/modules/rhsm_repository.py

@@ -36,6 +36,10 @@ options:
     description:
       - If state is equal to present or disabled, indicates the desired
         repository state.
+      - |
+        Please note that V(present) and V(absent) are deprecated, and will be
+        removed in community.general 10.0.0; please use V(enabled) and
+        V(disabled) instead.
     choices: [present, enabled, absent, disabled]
     default: "enabled"
     type: str
@@ -253,6 +257,14 @@ def main():
     state = module.params['state']
     purge = module.params['purge']
 
+    if state in ['present', 'absent']:
+        replacement = 'enabled' if state == 'present' else 'disabled'
+        module.deprecate(
+            'state=%s is deprecated; please use state=%s instead' % (state, replacement),
+            version='10.0.0',
+            collection_name='community.general',
+        )
+
     repository_modify(module, state, name, purge)