library: Add radosgw_caps to manage capabilities

library: Add radosgw_caps to manage capabilities

This commit add `radosgw_caps` module to be able to manage RadosGW users
capabilities.

Usage from module's documentation:
```YAML
- name: add users read write and all buckets capabilities
  radosgw_caps:
    name: foo
    state: present
    caps:
      - users=read,write
      - buckets=*
- name: remove usage write capabilities
  radosgw_caps:
    name: foo
    state: absent
    caps:
      - usage=write
```

This module support check mode by simulating the original `radosgw-admin`
behavior when adding capabilities.

Signed-off-by: Mathias Chapelain <mathias.chapelain@proton.ch>
(cherry picked from commit 65003f4ff90413094d46b682b78f6d749fcc2747)