[Business Guide] Clarify the process for making PRand handling "epic" changes in CHARTER

[anajsana]

Clarify in the charter the process for making pull requests (one file per PR, or multiple files if logically related) and the process for handling "epic" changes that span multiple files, using issues as anchors for related pull requests

Action Needed:

• Ana creates PR
• Reviewed and merged by WG reviewers