Ensure s.json thumb sizes are emitted in sizes from named query manifests and single-asset manifests

[tomcrane]

...so that clients can see what sized thumbs were created in bulk, for a named query, as well as individually.

Clients including the DDS.

At the moment protagonist deduces these sizes, so is potentially prone to rounding errors.
It won't be doing any deducing in future, just reading the sizes that cantaloupe made.

Requirement outlined above resulted in RFC being written (#767)

Update after RFC

RFC documents how metadata that can be read in bulk will be stored in AssetApplicationMetadata.

This ticket is blocked by #787 - once that is done we will have the AssetApplicationMetadata table available. This ticket is then to update classes involved in NQ + single-asset manifest generation (likely IIIFManifestBuilder and/or IIIFCanvasFactory) to read the thumbnail sizes generated, rather than deducing them.

However, when first introduced, and possibly for some time after, this new table won't be populated with "ThumbSizes" metadata value for every asset. So until that happens we need a method of attempting to read the actual values but falling back to calculating if there is no "ThumbSizes" metadata.

Initially upon release all new-format (ie using IIIF Size Param) thumb sizes will be based on confined sizes (!w,h) so we will be able to calculate them using existing methods in AssetX (updating method to only calculate confined thumb sizes).

Implementation points:

• We don't want to .Include() in the base NQ IQueryable generator - need a hook to include relevant data only depending on projection.
• It doesn't feel correct for Orchestrator to load assets with PolicyData. It will load ImageDeliveryChannel with PolicyId - this can be used to load + cache PolicyData if required (use same local caching mechanism as is currently happening with ThumbsPolicy).
• As well as "sizes the sizes read here need to populate the "thumbnail" property on manifest

Acceptance Criteria

• Named query and single-item manifests output sizes property read from database
• Where no thumbs sizes found in database calculate from image dimensions + policyData
• Logic to fallback to calculating should be controllable by a config flag - this should be a date to control fallback based on last image ingest date.

[donaldgray]

IIIFManifestBuilder is central class used for generating both NQ + single-asset manifests.

[tomcrane]

GetThumbnailSizesForImage should read S3 sizes.json.

[donaldgray]

protagonist/src/protagonist/Orchestrator/Infrastructure/IIIF/IIIFCanvasFactory.cs

Line 186 in 52a9f75

private async Task<ImageSizeDetails> GetThumbnailSizesForImage(Asset image)

is the method call to work out sizes per canvas (ie image).

We will need to take performance implications into account, particularly for larger NQs

[tomcrane]

Also need to make sure that "secret" thumbnails are also present in the sizes list.

[JackLewis-digirati]

This ticket will also need to cover handling skipped tests in NamedQueryTests and additional tests in ManifestTests to cover the retrieval of thumbnail sizes from the database (as opposed to s.json that it uses before this ticket)