cleanup file structure, dockerize app

cmd/app/handler/httpjson/health.go

@@ -0,0 +1,15 @@
+package httpjson
+
+import (
+	"net/http"
+
+	"github.com/labstack/echo/v4"
+)
+
+func (h *Handler) setupHealthCheckRoutes(app *echo.Echo) {
+	app.GET("/health", h.healthCheck)
+}
+
+func (h *Handler) healthCheck(c echo.Context) error {
+	return c.String(http.StatusOK, "OK")
+}