chore: wrap HTTP server in a dskit module (#71601)

* chore: wrap HTTP server in a dskit module

Much of the logic from this comes from the POC branch, so:
- credit for this work goes to everyone else
- mistakes are my own
This is needed to support microservice deployment modes.
* added an arbitrarily-chosen 30second timeout

pkg/modules/dependencies.go

@@ -9,6 +9,8 @@ const (
 	CertGenerator string = "cert-generator"
 	// GrafanaAPIServer is the Kubertenes API server for Grafana Resources
 	GrafanaAPIServer string = "grafana-apiserver"
+	// HTTPServer is the HTTP server for Grafana
+	HTTPServer string = "http-server"
 )
 
 // dependencyMap defines Module Targets => Dependencies
@@ -18,5 +20,5 @@ var dependencyMap = map[string][]string{
 	CertGenerator:    {},
 	GrafanaAPIServer: {CertGenerator},
 
-	All: {BackgroundServices},
+	All: {BackgroundServices, HTTPServer},
 }