Enable searching on other identifiers beyond Legal Name, BC Registries ID and BN

[swcurran]

What we would like is a process for being able to add identifiers from credentials other than those from BC Registries to the search index and autocomplete widget. Today, that would include the Cannibis permits and BuyBC licenses, but others are also possible. Define a generic mechanism/process to add new identifiers when needed, starting with the ones available at the time. Presumably, the registration of a credential type would include indicating what fields are searchable, and those would be added to the searching mechanism. The process does not have to be fully automated -- at least not until we are regularly adding new issuers.

When added, the main screen should be updated to list "Other identifiers", with a popup that includes a generated list of all combinations of other searchable identifiers, the source credential type and issuer.

[ianco]

This is done, we had to do this to make BN's searchable.

Just off the top of my head, we defined the bn_9 field as a "name": https://github.com/bcgov/von-bc-registries-agent/blob/master/bcreg-aca/config/services.yml#L340

I don't recall the particulars, or if we updated the docs (I suspect we didn't), I'll connect with @amanji and figure out what docs we need to update, or what other changes may be implied in your description above.