collection: implement file changelogs/changelog.yaml

[berndfinger]

The format of the file changelogs/changelog.yaml should be compliant with https://docs.ansible.com/ansible/latest/dev_guide/developing_collections_changelogs.html.

See also sap-linuxlab/community.sap_install#980 and sap-linuxlab/community.sap_install#503.

[berndfinger]

Solved in #84.