MM-13893: refactor config (#10230)

* refactor utils/config* to config/

* pull validateLdapFilter into app

* clean up Config/GetConfig/GetSanitizedConfig usage

Eliminate app.GetConfig() in favour of just using app.Config() directly,
but expose app.GetSanitizedConfig() for when the old behaviour was
required.

* web: isolate config setup

* TestInvitePeopleProvider: make config explicit

* regenerateClientConfig: avoid racey map access

* integrate watch flag into app.ConfigFile option

* make app.Option return an error

* release.mk: only cp static files from config/

* release.mk: fix cp static files from config/

* api4: TestPlugin cleanup

* s/c/cfg/ for clarity

* fix merge conflict

* testlib: allow customization of testlib driver name

migrations/helper_test.go

@@ -49,7 +49,7 @@ func setupTestHelper(enterprise bool) *TestHelper {
 		panic(err)
 	}
 
-	options := []app.Option{app.ConfigFile(tempConfig.Name()), app.DisableConfigWatch}
+	options := []app.Option{app.ConfigFile(tempConfig.Name(), false)}
 	options = append(options, app.StoreOverride(mainHelper.Store))
 
 	s, err := app.NewServer(options...)