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/access.go

@@ -31,6 +31,7 @@ type AccessResponse struct {
 	ExpiresIn    int32  `json:"expires_in"`
 	Scope        string `json:"scope"`
 	RefreshToken string `json:"refresh_token"`
+	IdToken      string `json:"id_token"`
 }
 
 // IsValid validates the AccessData and returns an error if it isn't configured