Revert "Merge branch 'jy-oauth-2' into 'master'"

Gemfile

Gemfile.lock

config/initializers/omniauth.rb

ee/spec/lib/omni_auth/strategies/group_saml_spec.rb

ee/spec/requests/omniauth_kerberos_spnego_spec.rb

vendor/gems/omniauth-azure-oauth2/Gemfile.lock

...auth-azure-oauth2/lib/omniauth/strategies/azure_oauth2.rb

.../gems/omniauth-azure-oauth2/omniauth-azure-oauth2.gemspec

vendor/gems/omniauth-cas3/Gemfile.lock

vendor/gems/omniauth-cas3/omniauth-cas3.gemspec

vendor/gems/omniauth-gitlab/Gemfile.lock

vendor/gems/omniauth-gitlab/omniauth-gitlab.gemspec

vendor/gems/omniauth-google-oauth2/CHANGELOG.md

vendor/gems/omniauth-google-oauth2/Gemfile.lock

vendor/gems/omniauth-google-oauth2/README.md

vendor/gems/omniauth-google-oauth2/examples/Gemfile

vendor/gems/omniauth-google-oauth2/examples/omni_auth.rb

...iauth-google-oauth2/lib/omniauth/google_oauth2/version.rb

...th-google-oauth2/lib/omniauth/strategies/google_oauth2.rb

...ems/omniauth-google-oauth2/omniauth-google-oauth2.gemspec