osd_types: factor out is_new_interval from check_new_interval

Signed-off-by: Samuel Just <sam.just@inktank.com>
PG: replace is_split, acting_up_affected with should_restart_peering

This way, we restart peering using the same criteria as
check_new_interval.

Fixes: #8104
Signed-off-by: Samuel Just <sam.just@inktank.com>
osd_types: remove the pool_id argument from (is|check)_new_interval

Signed-off-by: Samuel Just <sam.just@inktank.com>