Update Wiki for several issues

[Youssef1313]

https://github.com/dotnet/roslyn-analyzers/wiki

• Install Instructions

  • Shouldn't mention VS Extension.
  • Should mention the SDK, and possibly link to https://docs.microsoft.com/en-us/dotnet/fundamentals/code-analysis/overview#code-quality-analysis

• Apply a Code Fix for a Rule

  • There is a dead image link due to the movement from master to main. This link should be fixed.
  • There is a statement saying not all 100 code analysis rules in this extension have fixes associated with them., if the number of rules is now much greater than 100, this should be fixed either by removing the number at all, or fix the number.

• Configure a Rule

  • Dead image
  • It mentions ruleset, this should be updated for globalconfig and/or editorconfig

• FAQ

  • Shouldn't mention rulesets, or mention them as obsolete/deprecated.
  • A question saying Does this work with EditorConfig? is answered by "No". This feels outdated.
  • Links to NuGet package are for the old FxCopAnalyzers, not NetAnalyzers.

[Youssef1313]

Removing "help wanted" since community contributors don't have access to update the Wiki.

[Youssef1313]

Removing "help wanted" since community contributors don't have access to update the Wiki.

I think moving from GitHub Wiki to just a file makes more sense. I'm doing that in #6383.