Allow login through OpenID Connect (#16221)

* added OpenID Connect as an SSO option

* minor fixes

* added comments, removed an option that shouldn't be set

* fixed Gemfile.lock

* added newline to end of Gemfile.lock

* removed tab from Gemfile.lock

* remove chomp

* codeclimate changes and small name change to make function's purpose clearer

* codeclimate fix

* added SSO buttons to /about page

* minor refactor

* minor style change

* removed spurious change

* removed unecessary conditional from ensure_valid_username and added support for auth.info.name in user_params_from_auth

* minor changes

app/controllers/auth/omniauth_callbacks_controller.rb

@@ -4,8 +4,6 @@ class Auth::OmniauthCallbacksController < Devise::OmniauthCallbacksController
   skip_before_action :verify_authenticity_token
 
   def self.provides_callback_for(provider)
-    provider_id = provider.to_s.chomp '_oauth2'
-
     define_method provider do
       @user = User.find_for_oauth(request.env['omniauth.auth'], current_user)
 
@@ -20,7 +18,7 @@ class Auth::OmniauthCallbacksController < Devise::OmniauthCallbacksController
         )
 
         sign_in_and_redirect @user, event: :authentication
-        set_flash_message(:notice, :success, kind: provider_id.capitalize) if is_navigational_format?
+        set_flash_message(:notice, :success, kind: Devise.omniauth_configs[provider].strategy.display_name.capitalize) if is_navigational_format?
       else
         session["devise.#{provider}_data"] = request.env['omniauth.auth']
         redirect_to new_user_registration_url
@@ -33,7 +31,7 @@ class Auth::OmniauthCallbacksController < Devise::OmniauthCallbacksController
   end
 
   def after_sign_in_path_for(resource)
-    if resource.email_verified?
+    if resource.email_present?
       root_path
     else
       auth_setup_path(missing_email: '1')