Move heavily reused code to a library

[ro-tex]

Overview

There are some parts of this code that are independently re-invented in several other services (blocker, malware-scanner, abuse-scanner). We should identify the overlaps and export them into a shared library that we can maintain separately.

The most obvious example are the regexes for matching and extracting skylinks.

See SkynetLabs/abuse-scanner#2 (comment)

Design or Proposal