Instrumentation: Add histogram for request duration (#28364)

Signed-off-by: bergquist <carl.bergquist@gmail.com>
(cherry picked from commit edbaa9d681)

pkg/setting/setting.go

@@ -344,6 +344,10 @@ func (c Cfg) IsDatabaseMetricsEnabled() bool {
 	return c.FeatureToggles["database_metrics"]
 }
 
+func (c Cfg) IsHTTPRequestHistogramEnabled() bool {
+	return c.FeatureToggles["http_request_histogram"]
+}
+
 type CommandLineArgs struct {
 	Config   string
 	HomePath string