Background

In T300#12742, @matt wrote:

We're now starting to add more custom properties on Collections (e.g. with Web Monetization support in #369 and {T464}). So with this, I think we should switch from using the collectionattributes table to a new collections column: attributes, containing a JSON object of properties for the collection.

Besides reducing database queries, it'll also ease Collection fetching and make the process more consistent.

Implementation

As part of this schema change, we'll also need to migrate existing rows from the collectionattributes table to the column.