[FEATURE] Create a configuration page to enable resources

Problem/Motivation

Enabling all resources at the same time seems a little but too much. We should allow users to opt-in.

Proposed resolution

We should have all resources disabled by default. Then a configuration page could allow a user to enable resources.

Remaining tasks

1. Think about the implications of having an enabled resource that points to an entity of a disabled resource.
2. Have resources be disabled by default.
3. Create a configuration page to allow toggle resources on/off.
4. Use the configuration object, created for the configuration above, to enable / disable resources.

User interface changes

A configuration page under /admin/config/services/jsonapi.