Add database backup scripts

[Jonxslays]

This PR adds 4 scripts for taking backups of the WOM and WOM Bot databases.

• wom-backup.sh - This script will run on a cron timer and is the entrypoint for the other scripts.
• wom-dump.sh - This script performs the dumping of an individual database.
• wom-prune.sh - This script handles pruning old backups from the backup server.
• wom-upload.sh - This script handles pruning the local backups and uploading them to the backup server.

TODO

• Create an SSH key for the scripts to use to connect from the wom server to the backup server.
• Create a webhook for the scripts to send details of failed backups.

Worth noting that when calling these scripts and passing a directory argument, never include the trailing slash - the scripts take care of that.