MM-27688-OpenId Connect (#16222)

* implement openid connect

* update error strings

* handle OpenIdSetting.Secret as FAKE SETTING

* add openid to telemetry

* update config defaults, add telemetry

* fix bug with Office365

* Retrieve Office365 AuthData from IdToken

* fix linter

* add feature flag, reset defaults for config

* fix build error

* fix unit tests

* add authentication permission to Feature
Flags

* turn off feature flag

* set default button color

* set default button color only on openid

* fix for merging FeatureFlags in config

* remove feature flag

* revert config changes

* remove debug statements

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/gitlab/gitlab.go

@@ -91,7 +91,7 @@ func (glu *GitLabUser) getAuthData() string {
 	return strconv.FormatInt(glu.Id, 10)
 }
 
-func (m *GitLabProvider) GetUserFromJson(data io.Reader) (*model.User, error) {
+func (m *GitLabProvider) GetUserFromJson(data io.Reader, tokenUser *model.User) (*model.User, error) {
 	glu, err := gitLabUserFromJson(data)
 	if err != nil {
 		return nil, err
@@ -102,3 +102,11 @@ func (m *GitLabProvider) GetUserFromJson(data io.Reader) (*model.User, error) {
 
 	return userFromGitLabUser(glu), nil
 }
+
+func (m *GitLabProvider) GetSSOSettings(config *model.Config, service string) (*model.SSOSettings, error) {
+	return &config.GitLabSettings, nil
+}
+
+func (m *GitLabProvider) GetUserFromIdToken(idToken string) (*model.User, error) {
+	return nil, nil
+}