T3010

Depends on D13411

Add new endpoint /aliasesRegisteredAfterBlockheight/:queriedBlockheight to support looking up aliases registered after a given blockheight. This endpoint is designed to support developers who are looking to cache aliases locally and look up only the valid registrations they may be missing.

node index.js
In web browser, navigate to http://localhost:5000/aliasesRegisteredAfterBlockheight/775000 and note response
Play around with blockheight number, i.e increase it to remove the first couple of responses, confirm response adjusts correctly
Try with a string instead of a number for blockheight and confirm error response