move remaining client tools to pbs-tools/datastore

pbs-datastore now ended up depending on tokio after all, but
that's fine for now

for the fuse code I added pbs-fuse-loop (has the old
fuse_loop and its 'loopdev' module)
ultimately only binaries should depend on this to avoid the
library link

the only thins remaining to move out the client binary are
the api method return types, those will need to be moved to
pbs-api-types...

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

pbs-datastore/src/lib.rs

@@ -195,6 +195,7 @@ pub mod file_formats;
 pub mod index;
 pub mod key_derivation;
 pub mod manifest;
+pub mod paperkey;
 pub mod prune;
 pub mod read_chunk;
 pub mod store_progress;