[Mellanox] route config/set/delete performance improvement(#18801)

- Why I did it
Increase significantly the rate of routes config/set/delete to HW.

- How I did it
Add required flag in sai.profile and increase orchagent bulk size.

- How to verify it
Measure rate of route set/del operations at scale.

platform/mellanox/docker-syncd-mlnx/sai-common.profile

@@ -1,2 +1,3 @@
 SAI_DUMP_STORE_PATH=/var/log/mellanox/sdk-dumps
 SAI_DUMP_STORE_AMOUNT=10
+SAI_ASYNC_ROUTING_ENABLED=1