[+] add datum signer

modules/chain/dap_chain.c

@@ -298,6 +298,9 @@ static uint16_t s_datum_type_from_str(const char *a_type_str)
     if(!dap_strcmp(a_type_str, "transaction")) {
         return DAP_CHAIN_DATUM_256_TX;
     }
+    if (!dap_strcmp(a_type_str, "signer")) {
+        return DAP_CHAIN_DATUM_SIGNER;
+    }
     return DAP_CHAIN_DATUM_CUSTOM;
 }