Add a new module containing key-related functions and schemata from all
over, code moved is not changed as much as possible.
Requires adapting some 'use' statements across proxmox-backup-client and
putting the XDG helpers quite cozily into proxmox_client_tools/mod.rs
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
Have a single common function to get the BaseDirectories
instance and a wrapper for `find()` and `place()` which
wrap the error with some context.
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
