Reintegrate ckanext-saml2auth upstream into catalog.data.gov

[btylerburton]

User Story

In order to reduce our maintenance burden, Data.gov team wants investigate whether we can reintegrate catalog.data.gov with the upstream version of the ckanext-saml2auth extension.

Reference:

• GSA/ckanext-saml2auth

Acceptance Criteria

[ACs should be clearly demoable/verifiable whenever possible. Try specifying them using BDD.]

• GIVEN [a contextual precondition]
  [AND optionally another precondition]
  WHEN [a triggering event] happens
  THEN [a verifiable outcome]
  [AND optionally another verifiable outcome]

Background

[Any helpful contextual notes or links to artifacts/evidence, if needed]

Security Considerations (required)

[Any security concerns that might be implicated in the change. "None" is OK, just be explicit here!]

Sketch

• Check if catalog builds and functions correctly with ckanext-saml2auth upstream.
  • Reintegrate with upstream.

[nickumia-reisys]

This is our only customization:

• added excpetion type for unspportedbinding. ckanext-saml2auth#1

It was merged upstream:

• added exception type for UnsupportedBinding from SLO. keitaroinc/ckanext-saml2auth#72