First pass on adding remote backups

+ Added remote_backup.rs to handle remote backup logic
+ Added `remote` section to the config for optional remote backup setup
+ Using ssh2 rust library for SFTP support
+ small tweaks

src/main.rs

@@ -6,6 +6,7 @@ mod chunk_coordinate;
 mod config;
 mod discord;
 mod region;
+mod remote_backup;
 mod restore;
 
 use crate::backup::{convert_backup_to_sp, do_backup};