fix(maas): clean up node state before removal

[xtrusia]

MAAS node removal used the short hostname to clean up services that may be registered with the machine FQDN.
It could also remove Juju units without cleaning up their Cinder service records or MicroCeph OSDs.
This left stale state after the node was removed.

Preserve the FQDN returned by MAAS and use it to remove Nova services and Neutron agents after the target MicroOVN unit has stopped. Verify that no exact-host records remain.

Disable matching Cinder volume services before removing the cinder-volume unit. Remove their service records through a healthy Cinder control-plane unit afterward, matching both the short hostname and FQDN.

Remove DB-backed MicroCeph OSDs before removing the MicroCeph unit.
Compare the MicroCeph database with the CRUSH tree before making changes and stop removal when the two sources disagree.
Force removal passes the supported MicroCeph safety flags without hiding cleanup failures.

Closes-Bug: LP: #2163212

QA steps

source admin-openrc
TARGET=pr902-node04
SURVIVING_CEPH_UNIT=microceph/2

sunbeam cluster list --format yaml
juju status -m openstack-machines
openstack compute service list --service nova-compute -f value -c Host -c State -c Status
openstack network agent list -f value -c Host -c 'Agent Type' -c Alive -c State
openstack volume service list -f value -c Binary -c Host -c Status -c State
juju ssh -m openstack-machines "$SURVIVING_CEPH_UNIT" -- sudo microceph disk list
juju ssh -m openstack-machines "$SURVIVING_CEPH_UNIT" -- sudo microceph.ceph osd tree

Both commands stopped at the expected two-node replica and three-OSD safety checks, respectively:

sunbeam cluster remove --no-hints "$TARGET"
sunbeam cluster remove --force --no-hints "$TARGET"

Only in this disposable two-node lab, I removed the target OSD with MicroCeph's safety-check override, then retried:

juju ssh -m openstack-machines microceph/3 -- sudo microceph disk remove osd.3 --timeout 1800 --bypass-safety-checks --confirm-failure-domain-downgrade
sunbeam cluster remove --force --no-hints "$TARGET"

sunbeam cluster list --format yaml
juju status -m openstack-machines
openstack compute service list --service nova-compute -f value -c Host -c State -c Status
openstack network agent list -f value -c Host -c 'Agent Type' -c Alive -c State
openstack volume service list -f value -c Binary -c Host -c Status -c State
juju ssh -m openstack-machines "$SURVIVING_CEPH_UNIT" -- sudo microceph disk list
juju ssh -m openstack-machines "$SURVIVING_CEPH_UNIT" -- sudo microceph.ceph osd tree
juju ssh -m openstack-machines "$SURVIVING_CEPH_UNIT" -- sudo microceph.ceph health detail

The final removal exited 0. pr902-node04 was absent from Sunbeam, Juju, Nova, Neutron, Cinder, MicroCeph disks, and the CRUSH tree.
The empty CRUSH host was removed.
MicroOVN reapply kept only machine 0 and token distributor 0.
The surviving MicroOVN unit and osd.1 stayed active.

For CRUSH map removal, redeployed them. with above, delete osd not allowed because of min osd count.

The cluster had four OSDs: three on pr902-node03 and one on pr902-node04.

sunbeam cluster remove --force --no-hints "$TARGET"

The command exited 0 without manual OSD removal or --bypass-safety-checks.
The target OSD and CRUSH host were removed.

[hmlanigan]

Please add QA steps to the PR description.

Please update the last two commit messages to include why the change is needed.