Add Gemnasium dependency check to SAST

Description

Gemnasium has great, fast vulnerability checking for dependencies for several languages. We should add it to our SAST.

Proposal

The first iteration will include improvements to current gl-sast tool in order to:

• add dependency checks for php projects
• add dependency checks for python projects
• add better dependency checks for javascript and ruby

It will not remove any of the current features, and will manage to normalize results to avoid duplicates created by similar tools.