ui: ceph: osd: set default icon for other crush types

ui: ceph: osd: set default icon for other crush types

Some users have a more complicated CRUSH hierarchy, for example with a
stretched cluster. The additional hierarchy steps (datacenter, rack,
room, ...) are shown in the OSD panel. Showing a generic icon for any
CRUSH types that have not a specific icon configured will make it easier
to navigate the tree as it will not look somewhat broken and empty.

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>