Move fetch_ordered_annotations into a new annotation service

[jon-betts]

For:

• Move annotation CRUD actions into a service #7932

This is potentially part of a series of PRs to move the storage file into a service for altering annotations.

This is intended to:

• Make this part of h more like our normal pattern of services
• Collect similar behavior into the same place

Changes in the PR

This isn't a straight lift and shift. In addition to moving the function the following was changed:

• We don't accept a general function to mess with the query
• We only ever used this to eager load things
• This concentrates the responsibility and testing for eager loading to the service
• Changed the name to get_annotations_by_id as the ordered bit seems like an implementation detail. I would expect to have to point out of the order came back random, rather than the other way around