[alias-server] Deprecate local script lib

Summary:
These functions were originally written locally to support alias-server. They were then ported to ecash-script library in modules/. This lib was also implemented in alias-server but at the time forgot to remove the old files.

Delete them.

Test Plan: npm test

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D14519