mie: start implementing ir memory->text conversion

mie/convert/text-read.c

@@ -0,0 +1,7 @@
+#include "convert.h"
+
+b_status read_value_from_text(
+	struct mie_ir_converter *converter, struct mie_value **out)
+{
+	return B_ERR_NOT_SUPPORTED;
+}