Introduce go chi web framework as frontend of macaron, so that we can move routes from macaron to chi step by step (#7420)

* When route cannot be found on chi, go to macaron

* Stick chi version to 1.5.0

* Follow router log setting

vendor/github.com/go-chi/chi/middleware/profiler.go

@@ -0,0 +1,55 @@
+package middleware
+
+import (
+	"expvar"
+	"fmt"
+	"net/http"
+	"net/http/pprof"
+
+	"github.com/go-chi/chi"
+)
+
+// Profiler is a convenient subrouter used for mounting net/http/pprof. ie.
+//
+//  func MyService() http.Handler {
+//    r := chi.NewRouter()
+//    // ..middlewares
+//    r.Mount("/debug", middleware.Profiler())
+//    // ..routes
+//    return r
+//  }
+func Profiler() http.Handler {
+	r := chi.NewRouter()
+	r.Use(NoCache)
+
+	r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, r.RequestURI+"/pprof/", 301)
+	})
+	r.HandleFunc("/pprof", func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, r.RequestURI+"/", 301)
+	})
+
+	r.HandleFunc("/pprof/*", pprof.Index)
+	r.HandleFunc("/pprof/cmdline", pprof.Cmdline)
+	r.HandleFunc("/pprof/profile", pprof.Profile)
+	r.HandleFunc("/pprof/symbol", pprof.Symbol)
+	r.HandleFunc("/pprof/trace", pprof.Trace)
+	r.HandleFunc("/vars", expVars)
+
+	return r
+}
+
+// Replicated from expvar.go as not public.
+func expVars(w http.ResponseWriter, r *http.Request) {
+	first := true
+	w.Header().Set("Content-Type", "application/json")
+	fmt.Fprintf(w, "{\n")
+	expvar.Do(func(kv expvar.KeyValue) {
+		if !first {
+			fmt.Fprintf(w, ",\n")
+		}
+		first = false
+		fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value)
+	})
+	fmt.Fprintf(w, "\n}\n")
+}