lnrpc: modify gettransaction parameters

This commit adds index_offset and max_transactions to the list
of parameters passed during gettransactions call. index_offset
specify transactions to skip and max_transactions the total
transactions returned

lnrpc/lightning.proto

@@ -757,6 +757,18 @@ message GetTransactionsRequest {
 
     // An optional filter to only include transactions relevant to an account.
     string account = 3;
+
+    /*
+    The index of a transaction that will be used in a query to determine which
+    transaction should be returned in the response.
+    */
+    uint32 index_offset = 4;
+
+    /*
+    The maximal number of transactions returned in the response to this query.
+    This value should be set to 0 to return all transactions.
+    */
+    uint32 max_transactions = 5;
 }
 
 message TransactionDetails {