Search: Add search index configuration options (#55525)

* Search: externalize config

* Search: update config descriptions

* Search: fix value

* Search: fix

* update

* Search: revert config values

* Search: rename copy/paste

* Search: fix tests

pkg/setting/setting.go

@@ -455,6 +455,8 @@ type Cfg struct {
 
 	Storage StorageSettings
 
+	Search SearchSettings
+
 	// Access Control
 	RBACEnabled         bool
 	RBACPermissionCache bool
@@ -1028,6 +1030,7 @@ func (cfg *Cfg) Load(args CommandLineArgs) error {
 
 	cfg.DashboardPreviews = readDashboardPreviewsSettings(iniFile)
 	cfg.Storage = readStorageSettings(iniFile)
+	cfg.Search = readSearchSettings(iniFile)
 
 	if VerifyEmailEnabled && !cfg.Smtp.Enabled {
 		cfg.Logger.Warn("require_email_validation is enabled but smtp is disabled")