Project maintenance updates

[xperiandri]

Description

• Migrate to default .gitignore
• Updated Paket to 7.2.1
• Update Fantomas to 6.3.10
• Update FsDocs to 19.1.0
• Update .NET SDK on CI to 6.0.424
• Make .editorconfig more safe

• boy scout rule: "leave the code behind in a better state than you found it" (fix warnings, obsolete members or code-style in the places you worked in)
• Fake API guideline is honored

[Numpsy]

/home/runner/work/FAKE/FAKE> "dotnet"  fantomas src/app/ src/template/ src/test/ --recurse --check (In: false, Out: false, Err: false)
Unhandled exception. System.IO.DirectoryNotFoundException: Could not find a part of the path '/home/runner/work/FAKE/FAKE/--recurse'.

I think Fantomas 6 made the folder searching recursive by default, and deprecated the command line flag for it - so ---recurse can be removed from the invocation?

[Numpsy]

Is it worth updating Paket to v8 now, or leave that till later?

[xperiandri]

I would release this changes to v6 and then updated to v8

[Thorium]

The build failure of this comes because Paket v7 cannot handle component having dependencies of .net8. This is already fixed in master by Paket update to v8, but this commit has explicit Paket v7 change.

Thus I think best way could be git cherry-pick 112461702ff11682a90a2c15129700e5c831fc5f (.gitignore) and
git cherry-pick 51566248dd972b5699c8bd08cb1163bad9317be1 (.editorconfig) and well, the Fantomas update is not very high priority.

I'd first merge other PRs and release new version(s) (how is this released? To NuGet/dotnet-tools/...?) and then when all is good, then re-consider the Fantomas update.