[alias-server] [p11] Complete function set to achieve final alias registration result

Summary:
T2922

Depends on D13112

This diff completes the logic necessary to get valid alias registration txs from a designated registration address, including logic for rejecting duplicate alias registrations and duplicate alias registrations in the same blockheight.

Test Plan:
node index.js
Review generated files in test/mocks/generated/
npm run test

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D13115