Clean up Old Branches from Github repo

[prernaadev01]

Problem description

As per the discussion b/w Alex and Giuseppe, we have +5k commits ahead of main in develop, which is not apt after our 3.0 Guardian release.
Also, we see also 753 branches at the moment still open on the main repo

Requirements

We need to clean up old branches in main and develop branch to make our github repo more stable and consistent and to avoid unnecessary merge.

Definition of done

How do we know we've fully dealt with it?

Acceptance criteria

What are the criteria by which we determine if the issue has been resolved?