Add first-load tracking attributes to `makeGetMixin`

The makeFindMixin already included data for first-load tracking. For example, a videos service has two boolean attributes: haveVideosBeenRequestedOnce and haveVideosLoadedOnce. This adds feature parity for the makeGetMixin and adds the following attributes:

• has${capitalizedResource}BeenRequestedOnce
• has${capitalizedResource}LoadedOnce

These attributes can now be used to track first-load scenarios in the makeGetMixin.