Add additional arguments or new endpoint for exposed Metadata Displays (Annotations)

[DiegoPino]

What?

Sometimes you want to have extra arguments that can be used to compute/make decisions in your Exposed Metadata Displays (inside the Twig template) e.g for W3C annotations where we want "Which file's" Annotations to generate.

This is a simple add-on. Would allow admin users to select a simple path

e.g
/ado/UUID/metadata/iiifv2/manifest.jsonld OR --> Current
/ado/UUID/metadata/EXTRAARGUMENT/iiifv2Annon/annons.jsonld --> Additional

I would also like to add a REGEX or length/format check to the EXTRAARGUMENT

Then all this will still call: https://github.com/esmero/format_strawberryfield/blob/main/format_strawberryfield.routing.yml#L81

But with a wrapper method and with some Cleanup/Sanity checking logic.

I would also allow via a config 2 or 3 GET Arguments which can be set at the Config page with "name" -> "type", constraints, either a REGEX OR an set of possible Options. This would apply to both endpoints, e.g

/ado/UUID/metadata/EXTRAARGUMENT/iiifv2Annon/annons.jsonld?PAGE=1&LIMIT=10

This is what is needed really for OAI-PMH, etc too. So good to have

@alliomeria @aksm @giancarlobi @patdunlavey