Lookup results by output reference

[KtorZ]

Describe your idea, in simple words.

Kupo is currently geared towards addresses and fetching by address. However, results also contain useful information that can be handy to query such as output references (transaction id + output index) or assets.

This ticket is about providing HTTP endpoints to querying results by output references and/or by transaction id.

Why is it a good idea?

It makes the API more flexible and enable a wider variety of use-cases. It is also a low-hanging fruit since the output reference is already stored in the database and is even the primary key of the table (though, not isomorphic to an INTEGER and thus, would still require extra indexing).

Are you willing to work on it yourself?

Yes.

[KtorZ]

Done in #54.