sim: implement skip-round command for crm/lrm

sim: implement skip-round command for crm/lrm

This allows to simulate situations where there's some asymmetry
required in service type scheduling, e.g., if we the master should
not pickup LRM changes just yet - something that can happen quite
often in the real world due to scheduling not being predictable,
especially across different hosts.

The implementation is pretty simple for now, that also means we just
do not care about watchdog updates for the skipped service, meaning
that one is limited to skip two 20s rounds max before self-fencing
kicks in.

This can be made more advanced once required.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>