RHDHPAI-29: Add yaml formatting validation

[jrichter1]

What does this PR do?:

Adds simple yaml formatter linting to check PRs/commits, along with fixes that the formatter generated.

Which issue(s) this PR fixes:[

https://issues.redhat.com/browse/RHDHPAI-29

How to test changes / Special notes to the reviewer:

The CI action removes the any conditionals for the yamlfmt run. For local testing, I recommend commenting such lines.

[thepetk]

In general the updates look good to me! left only a minor comment to pin a dependency.

I'd suggest testing the updated code with software templates.

QQ: Do you have a test run of the action (for example in your fork)?

[jrichter1]

QQ: Do you have a test run of the action (for example in your fork)?

I did a run https://github.com/jrichter1/ai-lab-app/actions/runs/12807711620/job/35708874921, it doesn't really show much though, since there are no issues found.

[thepetk]

QQ: Do you have a test run of the action (for example in your fork)?

I did a run https://github.com/jrichter1/ai-lab-app/actions/runs/12807711620/job/35708874921, it doesn't really show much though, since there are no issues found.

Nice! Then I think just a quick test with the software templates to see that everything works fine. Mostly because we update a large number of files.

[jrichter1]

I've just run the template, and some of the variable substitution does not like being wrapped in single quotes, or rather the results might make for an invalid yaml when the value is not a string. Time to try without them...

[jrichter1]

In this form, the template works properly for me (feel free to not take my word for it though)

[johnmcollier]

Looks good from my end.

Some of the rearranging done by the yaml formatter had me worried that the nunjucks conditionals would get broken, but I compared them with what we have in main, and everything was preserved.