[pve-devel] Add 'action domain' lock and sue it for the ha-manager

[Thomas Lamprecht]

An 'action domain' locks guarantees that under all calls using an domainname the passed code executed atomically.
Indifferent if the have no common file to read/write to.

This can be used in the ha-manger where such behaviour is needed to avoid parallel changes to different configs and command files, to prevent race conditions, atomicity violations or a out of control closed loop.
This achievs that in an more generic way as until now we used the cfs_lock_storage function with an virtual storage id as a hack.
This is missleading and could also lead to an introduced bug in the future, as such hacks often get overlooked.