reduce task quota to 500 microseconds
reduce task quota to 500 microseconds

Currently we have 2 miliseconds as a default. We have been using 500
microseconds for ScyllaDB for a long time. We want to go even lower, but
we need some more infrastructure for that to happen without a (huge)
throughput decrease.

Signed-off-by: Glauber Costa <7ba9037b0dd006f9408bd45b94707becd5cd4e87@scylladb.com>

syuu1228/seastar,syuu1228/seastar,dreamsxin/seastar,avikivity/seastar,dreamsxin/seastar,cloudius-systems/seastar,dreamsxin/seastar,scylladb/seastar,avikivity/seastar,syuu1228/seastar,avikivity/seastar,scylladb/seastar,cloudius-systems/seastar,scylladb/seastar,cloudius-systems/seastar