AI-GCS: Create searching pipeline and REST API

[pombredanne]

I would like to have an end-to-end MatchCode.io search pipeline and its REST API.

This would be a functional system that works end-to-end starting from a codebase as an input, going then into the search proper, and the final output with the search results.

This means:

• Update MatchCode.io with end to end search pipeline
  • Ensure e2e search work in MatchCode.io API
  • Then, make a new release of MatchCode.io/PurlDB/ScanCode.io as needed
• A step-by-step guide to document the search API (and test it too)