cephadm: Add support for mpath devices to gather-facts

cephadm: Add support for mpath devices to gather-facts

multipath devices typically show as 2 device nodes, so
gather-facts needs to use the serial number of the
device to ensure the disk/flash counts and capacity
calculations are not twice as big as they should be.

In addition to logic changes,
- the device data includes new fields: disk_type (hdd|flash),
  serial, and alt_dev_name. The alt_dev_name shows the
  alternate device name for the same serial number (when a
  serial number is not present, this is just '')
- enclosure information (SES only) is included based
  on device serial number. This maps serial numbers to slots
  and provides a breakdown of the slot states
- the supported block device list now excludes loopback and
  mdraid (/dev/md*) devices

Fixes: https://tracker.ceph.com/issues/55489
Signed-off-by: Paul Cuzner <pcuzner@redhat.com>