Embed phoenix and serve it

So far Phoenix have been embedded into the binary and we can customize
the required config based on flags, env variables and optionally via
config file. For now I'm embedding the whole Phonix content, optherwise
the all-in-one binary `ocis` will get pretty complicated until we add
the generate commands to that repo as well and provide a mechanism to
inject the embedding.

pkg/router/debug/debug.go

@@ -0,0 +1,74 @@
+package debug
+
+import (
+	"io"
+	"net/http"
+
+	"github.com/go-chi/chi"
+	"github.com/go-chi/chi/middleware"
+	"github.com/owncloud/ocis-phoenix/pkg/handler/metrics"
+	"github.com/owncloud/ocis-phoenix/pkg/middleware/header"
+	"github.com/rs/zerolog/hlog"
+	"github.com/rs/zerolog/log"
+)
+
+// debug gets initialized by Router and configures the router.
+type debug struct {
+	token string
+	pprof bool
+}
+
+// Router initializes a router for the debug server.
+func Router(opts ...Option) *chi.Mux {
+	d := new(debug)
+
+	for _, opt := range opts {
+		opt(d)
+	}
+
+	mux := chi.NewRouter()
+
+	mux.Use(hlog.NewHandler(log.Logger))
+	mux.Use(hlog.RemoteAddrHandler("ip"))
+	mux.Use(hlog.URLHandler("path"))
+	mux.Use(hlog.MethodHandler("method"))
+	mux.Use(hlog.RequestIDHandler("request_id", "Request-Id"))
+
+	mux.Use(middleware.RealIP)
+	mux.Use(header.Version)
+	mux.Use(header.Cache)
+	mux.Use(header.Secure)
+	mux.Use(header.Options)
+
+	mux.Route("/", func(root chi.Router) {
+		if d.pprof {
+			root.Mount(
+				"/debug",
+				middleware.Profiler(),
+			)
+		}
+
+		root.Mount(
+			"/metrics",
+			metrics.Handler(
+				metrics.WithToken(d.token),
+			),
+		)
+
+		root.Get("/healthz", func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusOK)
+
+			io.WriteString(w, http.StatusText(http.StatusOK))
+		})
+
+		root.Get("/readyz", func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusOK)
+
+			io.WriteString(w, http.StatusText(http.StatusOK))
+		})
+	})
+
+	return mux
+}