Fix races / finally remove global app for good (#7570)

* finally remove global app for good

* test compilation fixes

* fix races

* fix deadlock

* wake up write pump so it doesn't take forever to clean up

app/command_channel_rename_test.go

@@ -9,6 +9,7 @@ import (
 
 func TestRenameProviderDoCommand(t *testing.T) {
 	th := Setup().InitBasic()
+	defer th.TearDown()
 
 	rp := RenameProvider{}
 	args := &model.CommandArgs{