Update COSMOS Model References to use CuratedUrl Model

[bishwaspraveen]

Description

After updating the models, we need to point all the existing COSMOS code to the new models. Additionally, we need new admin for the new models

• Update the api to point to the CuratedUrl model
• Update the frontend to point to the CuratedUrl model
• Likely, we can just do a repo-wide find and replace

Implementation Considerations

The initial design doc has been saved here for reference.

Deliverable

• frontend points to new model
• api points to new model
• serializers point to new model
• admin points to new model
• new admins for the dump and delta models (not the base, that is a meta model)
• anything else i forgot