Refactor policies implementation to support more than licenses

[tdruez]

Refactor policies implementation to support more than licenses.

The entire policies data is now stored on the ScanPipeConfig in place of the license_policy_index.

Also, a new method get_policies_dict methods is now available on the Project model to easily retrieve all the policies data as a dictionary.

Renamed for clarity:

• policy_index to license_policy_index
• policies_enabled to license_policies_enabled