implement left/right with callback

Signed-off-by: Peter Siegmund <developer@mars3142.org>

components/ruth/include/persistence.h

@@ -0,0 +1,8 @@
+#pragma once
+
+typedef struct
+{
+    char *name;
+
+    void (*save)(const char *key, const char *value);
+} persistence_t;