Github repo setup

[weichch]

This issue is used to track the tasks to setup for this repository.

• Move benchmarks out of Readme.md
• Add release notes
• Add contributing docs
• Add various templates, e.g. issue template
• Add Github actions and PR checks
  • Add to run on ubuntu-latest for .NET and .NET Core
  • Add to run on windows-latest (or appropriate) for .NET Framework
• Add build status to Readme.md
• Add CODEOWNERS file and restrict PR approval access
• Add Wiki