Local shovels: Update default credit

Author: dcorbacho

deps/rabbitmq_shovel/priv/schema/rabbitmq_shovel.schema

@@ -9,3 +9,7 @@
 {mapping, "shovel.topology.predeclared", "rabbitmq_shovel.topology.predeclared", [
      [{datatype, {enum, [true, false]}}]
 ]}.
+
+{mapping, "max_local_shovel_credit", "rabbitmq_shovel.max_local_shovel_credit", [
+    {datatype, integer}
+]}.

deps/rabbitmq_shovel/src/rabbit_local_shovel.erl

@@ -52,7 +52,7 @@
 %% sequence number initialized at an arbitrary point by the sender."
 %% See rabbit_amqp_session.erl
 -define(INITIAL_DELIVERY_COUNT, 16#ff_ff_ff_ff - 4).
--define(DEFAULT_MAX_LINK_CREDIT, 170).
+-define(DEFAULT_MAX_LINK_CREDIT, 1000).
 
 -record(pending_ack, {
                       delivery_tag,
@@ -677,7 +677,7 @@ maybe_grant_credit(#{source := #{queue_r := QName,
     handle_queue_actions(Actions, State).
 
 max_link_credit() ->
-    application:get_env(rabbit, max_link_credit, ?DEFAULT_MAX_LINK_CREDIT).
+    application:get_env(rabbitmq_shovel, max_local_shovel_credit, ?DEFAULT_MAX_LINK_CREDIT).
 
 grant_link_credit(Credit, MaxLinkCredit, NumUnconfirmed) ->
     Credit =< MaxLinkCredit div 2 andalso