do_with: Make do_with_state constructor a template
do_with: Make do_with_state constructor a template

This will allow constructing the tuple in place to avoid a call to the
move constructor.

This has no impact on text size and the perf difference is likely not
statistically significant.

Signed-off-by: Rafael Ávila de Espíndola <1975039f9046bf513b77c0c5639a0efc25f00e7f@scylladb.com>

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