Add Support for Folders/Collections for API Mocks in Mock Server

[sachinjain024]

Right now, Requestly Mock Server is used to create API Mocks (endpoints) by providing the API response and other details.

Here are some main requirements

• Users should be able to organize their mocks inside a collection
• A collection can have an optional path and all the nested mocks get the collection prefix automatically
• Users should be able to enable/disable a mock
• Users should be able to download mocks & collections as JSON file

This helps multiple users collaborate in the mock server. Users can also create Mocks within a collection and the collection can be named on the users or APIs hierarchy.

Corresponding Linear Ticket - https://linear.app/requestly/issue/RQLY-411/folderscollections-support-in-mocks (For Internal Team only)