Split up checks.c to hosts and service check modules

Hosts and services behaves quite similar, and should be treated
equally, and by the same methods. But they don't, so don't pretend to
be the same module.

Splitting up hosts checking and service checking in different files
makes it much easier to graps one module at the same time, so we can
refactor the scheduling of one module at the time to.

Signed-off-by: Max Sikstrom <msikstrom@op5.com>
Move check logic from utils.c to checks.c

There where "utils" in utils.c to handle checks, which was just only
check logic. Those should be part of the checks module, so we don't
have a dependency from utils.c to checks.c/h

Signed-off-by: Max Sikstrom <msikstrom@op5.com>
checks: Dont expose more methods than nessecary

We want to refactor the check module, so don't expose more methods than
nessecary.

Signed-off-by: Max Sikstrom <msikstrom@op5.com>
Move handling of orphancheck to service/host check module

To reduce the nubmer of exposed methods, and keep modules isolated,
move handling of service and host orphan checking seperate, and
isolated within the modules, as seperate events.

Signed-off-by: Max Sikstrom <msikstrom@op5.com>