Security, flexibility and bug fixes

This release comes with a bunch of new features and some bug fixes that made the utility more secure, flexible and save to use. That's the list of new features and bug fixes:

Features

• [#1] Vault secret backend - store important data (like passwords) in this secret backend and mdbackup will retrieve those secrets for you :)
• [#1] File secret backend - a fallback secret backend, secrets are read from the file system directly
• [#2] Backblaze integration - new cloud storage provider
• [40207c8] S3-like integration - new cloud storage provider for those S3-like services
• [#5] Moved to optional dependencies. Now if you don't use S3 nor Backblaze, those libraries won't get installed. Only install what you need.
• [#6] Ability to run some parts of the tool by adding some arguments when invoking it
• [#7] Bash scripts can now write debug logs. Just print a line starting with DEBUG: (space included).

Bug fixes

• [c440573] Handle exceptions when a bash script is running
• [c440573] Backup of a docker volume doesn't create the backup
• [#4] Follow symlinks when uploading backups
• [#8] [#9] Fix postgresql backups when running with a different user and/or requires a password to be supplied from terminal