FeatureFlags: Revert managing feature flags outside of settings.Cfg (#44382)

* Revert "FeatureToggles: register all enterprise feature toggles (#44336)"

This reverts commit f53b3fb007.

* Revert "FeatureFlags: manage feature flags outside of settings.Cfg (#43692)"

This reverts commit f94c0decbd.

pkg/setting/setting.go

@@ -342,10 +342,8 @@ type Cfg struct {
 
 	ApiKeyMaxSecondsToLive int64
 
-	// Check if a feature toggle is enabled
-	// @deprecated
-	IsFeatureToggleEnabled func(key string) bool // filled in dynamically
-
+	// Use to enable new features which may still be in alpha/beta stage.
+	FeatureToggles       map[string]bool
 	AnonymousEnabled     bool
 	AnonymousOrgName     string
 	AnonymousOrgRole     string
@@ -431,6 +429,41 @@ type Cfg struct {
 	UnifiedAlerting UnifiedAlertingSettings
 }
 
+// IsLiveConfigEnabled returns true if live should be able to save configs to SQL tables
+func (cfg Cfg) IsLiveConfigEnabled() bool {
+	return cfg.FeatureToggles["live-config"]
+}
+
+// IsLiveConfigEnabled returns true if live should be able to save configs to SQL tables
+func (cfg Cfg) IsDashboardPreviesEnabled() bool {
+	return cfg.FeatureToggles["dashboardPreviews"]
+}
+
+// IsTrimDefaultsEnabled returns whether the standalone trim dashboard default feature is enabled.
+func (cfg Cfg) IsTrimDefaultsEnabled() bool {
+	return cfg.FeatureToggles["trimDefaults"]
+}
+
+// IsDatabaseMetricsEnabled returns whether the database instrumentation feature is enabled.
+func (cfg Cfg) IsDatabaseMetricsEnabled() bool {
+	return cfg.FeatureToggles["database_metrics"]
+}
+
+// IsHTTPRequestHistogramDisabled returns whether the request historgrams is disabled.
+// This feature toggle will be removed in Grafana 8.x but gives the operator
+// some graceperiod to update all the monitoring tools.
+func (cfg Cfg) IsHTTPRequestHistogramDisabled() bool {
+	return cfg.FeatureToggles["disable_http_request_histogram"]
+}
+
+func (cfg Cfg) IsNewNavigationEnabled() bool {
+	return cfg.FeatureToggles["newNavigation"]
+}
+
+func (cfg Cfg) IsServiceAccountEnabled() bool {
+	return cfg.FeatureToggles["service-accounts"]
+}
+
 type CommandLineArgs struct {
 	Config   string
 	HomePath string