Add initial distributor CLI skeleton

internal/app/app.go

@@ -0,0 +1,14 @@
+package app
+
+import "errors"
+
+const Name = "distributor"
+
+// Version can be replaced at build time with -ldflags "-X .../internal/app.Version=<value>".
+var Version = "dev"
+
+var ErrNotImplemented = errors.New("not implemented")
+
+func VersionString() string {
+	return Name + " " + Version
+}