feat: get original source URL for entity

[akamick86]

Currently /search APi returns only program, it would be really great to return the source of the data. For example ofac.treasury.gov or even the link to the file download where the match came from.

[adamdecaf]

That's returned on the upcoming release with the /v2/search API. You can use the Go API to format an OFAC link right now. We're planning on adding that for other sources.

https://github.com/moov-io/watchman/blob/master/pkg/sources/ofac/display.go

[adamdecaf]

We should probably add a sources/display.go that accepts any search.Entity[T] and returns a source data URL.