Create/Update the instructions for syncing main branches with upstream

[heyselbi]

In branching strategy it was decided that we want to be upstream first. As a follow up action, a set of instructions and a template needs to be created/updated for all of the steps involved in syncing main branches of all repos that we manage with upstream/main.

Note: The template should also include how we work with odh-nightlies.

• Template/instructions on syncing the main branches with upstream
• (optional) Diagram how components are inter-related
• Add documentation on connection points with other teams
• Meet with the team and get the feedback on the template/instructions

[heyselbi]

Branching strategy doc:
https://docs.google.com/document/d/1mU1Yjj-YlN2EtzPERYV03nal4eEtEVncmk097epxFZI/edit?usp=sharing