better file organization

internal/errors/errors.go

@@ -0,0 +1,8 @@
+package errors_packets
+
+import "errors"
+
+var (
+	ErrResponseNot200OK     = errors.New("the request is not 200, download failed")
+	ErrCantFindManifestTOML = errors.New("can't find manifest.toml when trying to read the packagefile")
+)