reference the datastore in BackupGroup/Dir

And drop the base_path parameter on a first bunch of
functions (more reordering will follow).

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

pbs-datastore/src/lib.rs

@@ -142,6 +142,8 @@
 //! * / = no interaction
 //! * shared/exclusive from POV of 'starting' process
 
+#![deny(unsafe_op_in_unsafe_fn)]
+
 // Note: .pcat1 => Proxmox Catalog Format version 1
 pub const CATALOG_NAME: &str = "catalog.pcat1.didx";