Add scalafmt code formatter

[mdedetrich]

I would like to propose adding scalafmt to this codebase for the same set of obvious reasons why having a code formatter is a good idea. The typical problem with adding a code formatter is it causes merge conflicts for currently open PR's however scalafmt is in a stage where there are only a couple of major PR's which are planned to be merged soon i.e.

• Feature/workflow support #65
• Revert default JDK to 8 and GraalVM to 22.3.0 #136
• Ignore missing files when compressing target directories #66
• Support timeout for jobs and steps #98

The idea would be to introduce scalafmt after these PR's are merged. In regards to the actual scalafmt configuration, I am personally not that fussed. From introducing scalafmt to other projects usually there are 2 approaches to this, either try to find configuration that matches current style as much as possible (which can be a bit of work) or to just use something basic and deal with a large diff

@eed3si9n @armanbilge Thoughts?

[armanbilge]

just use something basic and deal with a large diff

that's fine. we can do the formatting in a separate commit and add it to .git-blame-ignore-revs.

[mdedetrich]

that's fine. we can do the formatting in a separate commit and add it to .git-blame-ignore-revs.

Perfect, specifically with .git-blame-ignore-revs I have already done this in Pekko and I can confirm it works without problems (almost every IDE/editor/tool that I can think of defers to git for git blame so it will respect .git-blame-ignore-revs).