PSA was monolothic, now split, with new features, like
a DB-backed partial pipeline. FB OAuth2 version also upped.
Partial pipelines don't get cleared except when necessary.
They persist for special cases like change of browser while
still mid-pipeline (i.e. email validation step).
Refactor, cleanup, and update of a lot of small things as well.
PLEASE NOTE the new `social_auth_partial` table.
third_party_auth contains a working settings mechanism, the start of the provider interface + 3 implementations (Google, Mozilla Persona, LinkedIn), and a stub for the auth pipeline. Modified existing lms settings files to use but deactivate the module.
