Age setup additional docs (version alignment and tests).

[jccampagne]

Add installation notes for:

• aligning PostgreSQL and Apache Age version to avoid issues like https://github.com/apache/age/issues/1991
• running installation tests

[jccampagne]

Happy to replicate this in the ReadMe of Apache Age source code (that's what I actually read first, instead of the doc website).

[jrgemignani]

I think these changes help add clarity to the process and the small grammar issue I noted can be cleaned up in a future commit if @jccampagne is unable to address it. Thoughts on merging @jrgemignani @eyab?

Should it be applied to master or new-web ?

[sorrell]

I think these changes help add clarity to the process and the small grammar issue I noted can be cleaned up in a future commit if @jccampagne is unable to address it. Thoughts on merging @jrgemignani @eyab?

Should it be applied to master or new-web ?

Great question! And this is something I was thinking about opening an issue for, as this repo has pretty confusing branch naming. At this point, the "docs" are generated off master and the "marketing" website is build on new-web. I think we should clean up that naming, but yes, this PR should go to master at this time.