Migrate to stateless app.App (#17542)

* add request context

* move initialialization to server

* use app interface instead of global app functions

* remove app context from webconn

* cleanup

* remove duplicated services

* move context to separate package

* remove finalize init method and move content to NewServer function

* restart workers and schedulers after adding license for tests

* reflect review comments

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

einterfaces/saml.go

@@ -4,13 +4,14 @@
 package einterfaces
 
 import (
+	"github.com/mattermost/mattermost-server/v5/app/request"
 	"github.com/mattermost/mattermost-server/v5/model"
 )
 
 type SamlInterface interface {
 	ConfigureSP() error
 	BuildRequest(relayState string) (*model.SamlAuthRequest, *model.AppError)
-	DoLogin(encodedXML string, relayState map[string]string) (*model.User, *model.AppError)
+	DoLogin(c *request.Context, encodedXML string, relayState map[string]string) (*model.User, *model.AppError)
 	GetMetadata() (string, *model.AppError)
 	CheckProviderAttributes(SS *model.SamlSettings, ouser *model.User, patch *model.UserPatch) string
 }