Create debug.md to help users debug grafana-operator

[NissesSenap]

Description

Should be a document where the maintainers can help users to debug the grafana-operator.

Adds links to debug.md from relevant documents.

Relevant issues/tickets

Type of change

• Bug fix (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)

Checklist

• This change requires a documentation update
• I have added tests that prove my fix is effective or that my feature works
• I have added a test case that will be used to verify my changes
• Verified independently on a cluster by reviewer

Verification steps