Rest API reorganization (#3624)

* reorg API

* reorg api

* fix system route

* remove newline

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

server/api/system.go

@@ -0,0 +1,26 @@
+package api
+
+import (
+	"net/http"
+
+	"github.com/gorilla/mux"
+)
+
+func (a *API) registerSystemRoutes(r *mux.Router) {
+	// System APIs
+	r.HandleFunc("/hello", a.handleHello).Methods("GET")
+}
+
+func (a *API) handleHello(w http.ResponseWriter, r *http.Request) {
+	// swagger:operation GET /hello hello
+	//
+	// Responds with `Hello` if the web service is running.
+	//
+	// ---
+	// produces:
+	// - text/plain
+	// responses:
+	//   '200':
+	//     description: success
+	stringResponse(w, "Hello")
+}