Add more providers to the OAuth login integration tests.
Add more providers to the OAuth login integration tests.

- Added saml, authentiq, cas3, and auth0
- Crowd seems to be a special case that will be handled separately.

axilleas/gitlabhq,jirutka/gitlabhq,mmkassem/gitlabhq,jirutka/gitlabhq,jirutka/gitlabhq,t-zuehlsdorff/gitlabhq,dreampet/gitlab,dplarson/gitlabhq,mmkassem/gitlabhq,dplarson/gitlabhq,jirutka/gitlabhq,mmkassem/gitlabhq,stoplightio/gitlabhq,dplarson/gitlabhq,iiet/iiet-git,axilleas/gitlabhq,dreampet/gitlab,iiet/iiet-git,t-zuehlsdorff/gitlabhq,stoplightio/gitlabhq,mmkassem/gitlabhq,iiet/iiet-git,axilleas/gitlabhq,stoplightio/gitlabhq,iiet/iiet-git,t-zuehlsdorff/gitlabhq,stoplightio/gitlabhq,dplarson/gitlabhq,axilleas/gitlabhq,dreampet/gitlab,dreampet/gitlab,t-zuehlsdorff/gitlabhq