[Enhancement] Implement Authorization/RBAC policies for repositories Module

[Utkar5hM]

Let's start with a basic rough sketch for implementation:

Two types of users:

• Regular/Developers
• Admins

Admins will have access to all repositories.

Updates to Repostiories Model:

• state (enum/bool): public or private
• if private, another array could be populated which is shared_with with a list of users ? we will have an option for devs to manually add a user to shared_with or generate a share token/url.