refactor: move DWN proxy server logic to separate file

nebula/nebula.go

@@ -1 +1,31 @@
 package nebula
+
+import (
+	"embed"
+	"io/fs"
+	"net/http"
+	"os"
+
+	"github.com/labstack/echo/v4"
+)
+
+//go:embed assets
+var embeddedFiles embed.FS
+
+func getFileSystem(useOS bool) http.FileSystem {
+	if useOS {
+		return http.FS(os.DirFS("assets"))
+	}
+
+	fsys, err := fs.Sub(embeddedFiles, "assets")
+	if err != nil {
+		panic(err)
+	}
+
+	return http.FS(fsys)
+}
+
+func UseAssets(e *echo.Echo) echo.HandlerFunc {
+	assets := http.FileServer(getFileSystem(true))
+	return echo.WrapHandler(assets)
+}