Add targetSource endpoint for fetching annotations based on targetSource

[svandaalen]

To integrate knaw-huc/textannoviz#128 into TAV, TAV needs an endpoint in Broccoli that allows for fetching of annotations based on the target.source.

A quick recap of what we discussed yesterday:

• Move the current bodyId endpoint from https://broccoli.tt.di.huc.knaw.nl/projects/republic/urn:republic:session-3816-num-95-resolution-3?overlapTypes=AttendanceList,RepublicParagraph,Attendant,Resolution,Reviewed,Session,Scan,Entity&includeResults=anno,iiif,text&views=self&relativeTo=Origin to https://broccoli.tt.di.huc.knaw.nl/projects/republic/bodyId/….
• Add a new canvasId endpoint, e.g., https://broccoli.tt.di.huc.knaw.nl/projects/republic/canvasId/…. Either give the canvasId after the slash, or make it a POST endpoint and send the canvasId and the parameters through JSON.
• The parameters should be the same between the bodyId and the canvasId endpoints.

The AR search query to fetch the Resolutions that belong to canvasId https://images.diginfra.net/api/pim/iiif/9c33830d-797f-4a14-a474-5017466700c7/canvas/93504486-522c-42f6-8001-d13829692f5c is:

{
  "target.type": "Canvas",
  "target.source": "https://images.diginfra.net/api/pim/iiif/9c33830d-797f-4a14-a474-5017466700c7/canvas/93504486-522c-42f6-8001-d13829692f5c",
  "body.type": "Resolution"
}

Bram noted that "target.type": "Canvas", could be left out. He also already created an index in AR to speed up this query.

[hayco]

@brambg mentioned that target.type is not even necessary in the query.
This could mean that we can abstract from calling this 'get by canvasID' to 'get by targetSource' or something similar, allowing for more use cases to be handled by the same endpoint.

[brambg]

Met de huidige target.type lijkt me dat geen probleem: de target.source van het ene target.type wordt nooit bij een ander target.type gebruikt.