fixing imports
moving base-py3 packages to base
removing py2 and py3 base requirement files
removing requirement-development-py2 and renamed the py3 to simple development
using newer version of factory boy
removing "hydrate" calls on features
added Evidence Manager to db abstraction layer, with hydration method
updated factories and tests about classifier features
cleaning imports and non used/deprecated factories
Merge branch '276-tests-fixing' into relational-storage