chore: update internal Backstage version to v1.42.5

[Parkreiner]

This PR is absolutely massive, but it's mostly "conceptually small" and gets the project back on track so that we can start making contributions more regularly.

Changes made

Will fill out shortly, once I have CI fully passing.

[Parkreiner]

My employment with Coder has ended, effective immediately. I will not be doing any further work on this PR, or in this repo.

Best of luck to those who need to maintain this going forward.

[Parkreiner]

@DevelopmentCats Just pinging you in case you missed this WIP PR. Not sure how much you would want to bring over, but this PR was a much more comprehensive update

I know you're probably crunching, and I don't want you to have to spin your wheels on getting onboarded more than you have to

[DevelopmentCats]

@DevelopmentCats Just pinging you in case you missed this WIP PR. Not sure how much you would want to bring over, but this PR was a much more comprehensive update

I know you're probably crunching, and I don't want you to have to spin your wheels on getting onboarded more than you have to

I actually made a branch from this branch in what im working on currently.

Thank you for pointing it out though it definitely was incredibly helpful! @Parkreiner