Migrate contribute section from scala-lang to a guide

[bishabosha]

Add a new guide based from https://scala-lang.org/contribute - I have copied the files over including their history, before performing updates on top.

• Add a single guide "Contributing to Scala"
• Rename Scala 3's "Contribution Guide" to "Scala 3 Contributing Guide"

Steps taken to migrate contribute docs and preserve history:

• Install git-filter-repo ( https://github.com/newren/git-filter-repo )
• clone scala-lang to scratch dir
• cd scratch/scala-lang - we are on branch main
• git checkout -b src-main
• remove remote: git remote rm origin
• remove everything except the files of interest: git filter-repo --force --path _contribute_resources --path contribute
• now record the hash of first commit on src-main: 6bea2efad6f3c3f41e43780dc937030f3515a323
• cd docs.scala-lang
• git add remote src-repo ../scratch/scala-lang
• git fetch src-repo
• git checkout -b pick-from-src-repo
• record current head commit on pick-from-src-repo: 4a79b3f6233060eba7b151e596c3ec601bfcb1d4
• play the commits of src-repo/src-main onto pick-from-src-repo: git filter-branch --parent-filter 'test $GIT_COMMIT = 6bea2efad6f3c3f41e43780dc937030f3515a323 && echo "-p 4a79b3f6233060eba7b151e596c3ec601bfcb1d4" || cat' HEAD
• add back the files from docs.scala-lang: git filter-branch --index-filter 'git reset 4a79b3f6233060eba7b151e596c3ec601bfcb1d4 -- .bundle .github .gitignore CODE_OF_CONDUCT.md Dockerfile Gemfile Gemfile.lock README.md _ba _books _cheatsheets _config.yml _data _de _es _fr _getting-started _glossary _includes _it _ja _ko _layouts _overviews _pl _plugins _pt-br _ru _sass _scala3-reference _sips _style _th _tour _zh-cn _zh-tw api books.md conduct.html contribute.md docker-compose.yml guides.md index.md learn.md news online-courses.md reference.md resources scala3 scripts tutorials.md' -f -- 4a79b3f6233060eba7b151e596c3ec601bfcb1d4..HEAD
• push to GitHub as move-contribute-from-scala-lang-precise-history

[bishabosha]

@julienrf I have addressed your comments from add-guides.md

[SethTisue]

@bishabosha what kind of review would you like from me here? I'm definitely strongly in favor of the change overall. And I appreciate the extra effort you took to preserve the version control history.

It would be time-consuming for me to go over the whole thing with a fine-tooth comb, so I'm inclined to just say "LGTM!", but if there are particular aspects of this you'd like feedback on, let me know.

[bishabosha]

what kind of review would you like from me here? I'm definitely strongly in favor of the change overall. And I appreciate the extra effort you took to preserve the version control history.

It would be time-consuming for me to go over the whole thing with a fine-tooth comb, so I'm inclined to just say "LGTM!", but if there are particular aspects of this you'd like feedback on, let me know.

@SethTisue Thank you for offering! I think it could be useful to update references to tools I do not understand, such as DBuild and Partest, which are linked from /contribute/tools.html (should there be more tools listed?) and http://localhost:4000/contribute/partest-guide.html, are there links that should be updated for these tools? As for general modernising, I think that could be done in future PRs, except for a general comb over for inclusive language purposes.

Edit: overall though, as these links still go to live webpages, changing them can wait to further PRs

[bishabosha]

I've added my final changes to keep things up to date

[SethTisue]

🎉