devices: dm uuid related function names

devices: dm uuid related function names

In the context of dm, 'device' refers to a dm device, but
in the context of lvm, 'device' refers to struct device.
Change some lvm function names to make that difference clearer.

dev_manager_get_device_list() -> dev_manager_get_dm_active_devices()
get_device_list() -> get_dm_active_devices()
device_get_uuid() -> dev_dm_uuid(), devno_dm_uuid()