Updating the documentation on Git workflows

What does this MR do and why?

Introduces a more detailed guideline for different Git workflows which can be used in GitLab while preserving the stress on GitLab Flow.

Screenshots or screen recordings

No visual changes

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #378297 (closed)