API to retrieve predefined categories of collections for the new Hub Dashboard UI

Problem Description: 

We are building a new landing page for Automation Hub using these designs from UXD. Based on the design the dashboard UI will contain sections representing prescribed categories of collections such as:

• Featured Collections
• My Collections
• Event-Driven Ansible Content
• Storage Collections
• System Collections

As discussed in the notes here these categories can be supported using tags and  collection marks.

We will need API endpoints to support retrieving the predefined/prescribed categories of collections.

Proposed Solution:

A new API endpoint to retrieve collection categories for the Dashboard UI:

For instance:

/collection-categories

The response would indicate the categories as well as the search key and search value that can be used to filter the collections for these categories using the collection version search API. See API Spec details in https://docs.google.com/document/d/1dUavgcFbdO_UIwbrsctEAIBuen2KGRJU1ep3l3_uY1M/edit#heading=h.2nr2txsxyclk