This acts just like FString except that we do reverse device name
translation on it. The only use is in the 'pvs-full' API where we
will use it (in a subsequent commit) to reverse translate the pv_name
field (a device name) before returning it from the daemon.
Compare this to the 'pvs' API which also returns a list of device
names, but using the generator's 'RStructList (RDevice,...)' return
type, where RDevice is similarly reverse translated.
Note in the library-side bindings, because the name has already been
translated in the daemon, we just treat it exactly the same as
FString. The vast majority of this patch is this mechanical change.
Without clarifying handle's lifetime, it is unable
to see how long the callbacks which the handle
owns will live. Then, Rust compiler will infer
that the callbacks have 'static lifetime. It is
not convenient for users.
