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>

app/context.go

@@ -6,6 +6,8 @@ package app
 import (
 	"context"
 
+	"github.com/mattermost/mattermost-server/v5/app/request"
+	"github.com/mattermost/mattermost-server/v5/plugin"
 	"github.com/mattermost/mattermost-server/v5/store/sqlstore"
 )
 
@@ -13,3 +15,14 @@ import (
 func WithMaster(ctx context.Context) context.Context {
 	return sqlstore.WithMaster(ctx)
 }
+
+func pluginContext(c *request.Context) *plugin.Context {
+	context := &plugin.Context{
+		RequestId:      c.RequestId(),
+		SessionId:      c.Session().Id,
+		IpAddress:      c.IpAddress(),
+		AcceptLanguage: c.AcceptLanguage(),
+		UserAgent:      c.UserAgent(),
+	}
+	return context
+}