Instead of using random hex characters from an md5sum, use a nice name
in all-caps similar to how Ceph does. This further helps prevent dupes
but also permits a changing health delta within a single event (which
would really only ever apply to plugin faults).
Since we already had a "details" field, simply move where it gets added
to the message later, in generate_fault, after the main message value
was used to generate the ID.
This ensures that certain faults e.g. Ceph status faults, will be
combined despite the added text in brackets, while still keeping them
mostly separate.
Also ensure the health text is updated each time to assist with this, as
this health text may now change independent of the fault ID.
