lsa: advertize our preferred maximum allocation size
lsa: advertize our preferred maximum allocation size

Let managed_bytes know that allocating below a tenth of the segment size is
the right thing to do.

scylladb/scylla,kjniemi/scylla,raphaelsc/scylla,scylladb/scylla,duarten/scylla,duarten/scylla,avikivity/scylla,avikivity/scylla,avikivity/scylla,duarten/scylla,scylladb/scylla,scylladb/scylla,raphaelsc/scylla,kjniemi/scylla,kjniemi/scylla,raphaelsc/scylla