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

app/enterprise.go

@@ -120,7 +120,7 @@ func (s *Server) initEnterprise() {
 	if ldapInterface != nil {
 		s.Ldap = ldapInterface(s.FakeApp())
 		s.AddConfigListener(func(_, cfg *model.Config) {
-			if err := utils.ValidateLdapFilter(cfg, s.Ldap); err != nil {
+			if err := validateLdapFilter(cfg, s.Ldap); err != nil {
 				panic(utils.T(err.Id))
 			}
 		})