(docs): add governance policies around using donation funds

[christian-bromann]

Proposed changes

The WebdriverIO project likes to start distributing the funds more equally to contributor within and outside the team. This PR adds some policies around how we distribute the money, who is eligible receiving it and a flow to have folks claim their funds.

Types of changes

• 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 to not work as expected)
• Documentation update

Checklist

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• I have added proper type definitions for new commands (if appropriate)

Further comments

This governance change has been discussed within the projects TSC chat room. I will go ahead and merge the PR in order to test the distribution flow.

Reviewers: @webdriverio/technical-steering-committee