[pve-devel] ha-manager: add ignore state v2

[Thomas Lamprecht]

V2 of this series is a refactored version of v1, the implementation behaves
the same.

The ignore state is the state where a service has a HA configuration but
wants to be unmanaged for a temporary time.
Deleting the service confiuration deletes also its comments, group
membership, recovery policy settings. While not much this was reported as
frustrating by some users.

The implementation choosen was favored over simply dropping the service
configuration entry on read fopr the following reasons:
* the Status API call uses the same methods for processing the resource
  config as the CRM, so the service would get invisible in the UI and CLI
  tools. This is missleading and may confuse users. You cannot change the
  service state over the UI anymore, as its entry is missing.
  This is naturally fixable but generates more changes than my apporach.
* adding the check in the Manager class is easier then adding a check to
  each ha environment (PVE2 and Sim)
* we can differ between a service removal and requesting that a service gets
  ignored and change the log output respectively, users can thus easier
  understand what happened.