add releases + changelog to github instead of just tag sources to allow watch updates

[Slach]

Related to:

• add github releases + changelog instead of just tag in github, to allow subscribe and watch updates via github trino-operator#558
• add github releases and changelog instead of just tag sources ot allow watch updates zookeeper-operator#789
• add github releases + changelog instead of just tag sources to allow watch updates via github watch kafka-operator#679

[Techassi]

Because https://github.com/stackabletech/decisions/issues/9 was not accepted, adding GitHub releases with appropriate changelogs would require a lot of manual work. There won't be any immediate work on this issue for now.

This topic might get re-visited in the future and thus will be kept open for reference.