[FEATURE] Evidence field for /kick

[janssensjelle]

Types of changes

What types of changes does your code introduce?
Put an x in the boxes that apply.

• Bugfix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality not to work as expected).
• Documentation Update (if none of the other choices applies).

Proposed changes

This PR adds the evidence option to the /kick command.
I have refactored the code a bit.

• moved the add_evicence_note to the ban helper
• Altered ban function + tests
• Added a test case for kicking a user and adding a note

I received a false positive from the lint saying the arrow import is unused, but this is false.

Checklist

Put an x in the boxes that apply.

• I have read and followed the CONTRIBUTING.md
  doc.
• Lint and unit tests pass locally with my changes.
• I have added the necessary documentation (if appropriate).

Additional context