Page and Card Metadata Database For Self Service Needs

**User Story**
As a Product Manager, I would like a database-like feature in DA, so we can access and maintain Page and Card Metadata Properties across multiple pages.

**Acceptance Criteria**
There are two scenarios to consider:
1. Read - for self-service reporting purposes
2. Write - for self-service bulk updates

### Read
- Authors and Product Managers can access this database to find Page Metadata properties
- Authors and Product Managers can access this database to find Card Metadata properties
- The list should contain the Page URL and the various properties associated with that page

**Additional Context**
- Enabling the ability to read the database will allow Product Managers to quickly get a report of whats going on on their pages
- This will also enable engineering to get out of the "run a script to produce a report" game and also standardize one of the ways we currently use our Query Index
- **Examples of past related tickets:**
- https://jira.corp.adobe.com/browse/MWPW-142287
- https://jira.corp.adobe.com/browse/MWPW-129025

### Write
- Authors can write to this database and the update is reflected in the DA doc as well
- Similar to AEM, maybe there is an ability to download a JSON, allowing authors to make changes to that JSON and then re-upload it with the changes reflected

**Additional Context**
- Enabling the ability to Write to the database will get Engineering and Authoring out of "petty" bulk updates that take too long and require content freezes (i.e. "We need to update tag A to tag B across all our BACOM pages") - taking us from weeks to days.
- **Examples of past related tickets:**
- https://jira.corp.adobe.com/browse/MWPW-143598
- https://jira.corp.adobe.com/browse/MWPW-141136

Start by reviewing the da-live architecture and the existing Query Index usage to identify where Page and Card Metadata are stored and exposed. Define the scope for read access and bulk write access, including JSON import/export and reflection into DA documents; done means authors and Product Managers can report on metadata and safely apply bulk updates.

Written by the indexing model from the issue text.