add documentation and dummy CONTRIBUTING.md

[ByteOtter]

What does this PR change?

Add additional documentation.

• docs directory for testsuite
• CODE_OF_CONDUCT.md
• dummy CONTRIBUTING.md

Tick the applicable box:

• [ ] Add new feature

• [ ] UI improvement

• [ ] Changed routing

• [ ] Security changes

• [ ] Testsuite
  

• [x] General Maintenance

UI changes

• No changes

  • [x] DONE

Documentation

• No documentation needed
  

• [x] DONE