client: expose all-file-systems option

Useful to avoid the need for a long (and possibly changing) list of include-dev
options in certain situations, e.g. nested ZFS file systems. The option is
already implemented and seems to work as expected. The checks for virtual
filesystems are not affected by this option.

Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>

src/bin/proxmox-backup-client.rs

@@ -875,6 +875,11 @@ fn keyfile_parameters(param: &Value) -> Result<(Option<Vec<u8>>, CryptMode), Err
                    description: "Path to file.",
                }
            },
+           "all-file-systems": {
+               type: Boolean,
+               description: "Include all mounted subdirectories.",
+               optional: true,
+           },
            keyfile: {
                schema: KEYFILE_SCHEMA,
                optional: true,