Use github to fetch ansible collections

On 30.09.2023, "old" ansible galaxy(galaxy.ansible.com) was replaced
with "galaxy ng"[1].
There was a bug [2][3][4] that was fixed only in a supported
ansible-core versions, so:
- v2.12.8
- v2.13.3
- v2.14.0 (and all newer versions)

All openstack-ansible versions up to Yoga are using older ansible-core
versions.
As a result, bootstrap-ansible.sh script fails with an error:

```
Skipping Galaxy server https://galaxy.ansible.com/api/. Got an
unexpected error when getting available versions of collection
ansible.netcommon:
'/api/v3/plugin/ansible/content/published/collections/index/ansible/netcommon/versions/'
```

This patch changes source for community collections from galaxy to github.

[1] https://www.ansible.com/blog/new-ansible-galaxy
[2] https://github.com/ansible/ansible/issues/81830
[3] https://github.com/ansible/ansible/issues/77911
[4] https://github.com/ansible/ansible/pull/78325

Related-Bug: #2038315
Depends-On: https://review.opendev.org/c/openstack/openstack-ansible-os_rally/+/897447
Change-Id: Iadbc89076a33517efb1d2ec64e2dbd996f862c8c

ansible-collection-requirements.yml

@@ -23,7 +23,9 @@ collections:
   # NOTE(noonedeadpunk): needs version in galaxy.yml to pull from git
   - name: ansible.netcommon
     version: 2.5.1
-    source: https://galaxy.ansible.com
+    source: https://github.com/ansible-collections/ansible.netcommon
+    type: git
   - name: openvswitch.openvswitch
     version: 2.0.2
-    source: https://galaxy.ansible.com
+    source: https://github.com/ansible-collections/openvswitch.openvswitch
+    type: git