Bugfix and Bash shellcheck updates

Updated to make Shellcheck happy, then had to test and bugfix after those updates...

Full Changelog: v1.0.0...v1.0.1

Initial Public Release

• Uses a .conf file for backup options: Settings for type of backup, backup location, services and Docker containers, image-backup options, messaging and logging can be saved as the defaults for the backup. Backup file and log retention and post image creation options are also set in the .conf file.
• Command Line Options to Override .conf Settings: Command line options for starting a user backup or initial image-backup image so those can be run without changing the .conf settings file.
• Automatic Folder Structure and File Naming: Backup will be placed in the backup location specified in the .conf file under folders by hostname and OS Version with a filename created using that hostname, OS Version and date & time stamp.
• Stopping and Re-starting of Services and Docker Containers: If specified in the .conf file, prior to the backup, the specified Services and Docker containers will be stopped then re-started after the backup completes.
• Smart Incremental Backups: Uses image-backup and rsync to update the most recent existing image, saving time and SD card wear.
• Auto-Shrink: For backup images that will not be used for incremental backups, pishrink.sh can be used to keep image files as small as possible by further compressing them then using gzip on them.
• Multi-Partition Trim: If running from an SD card, dynamically finds and trims both /boot and / partitions.
• Smart Notifications: Sends success/alerts to Telegram, Gotify or Ntfy with a backup log if set to do so.
• Environment Aware: Automatically detects tool paths (image-backup, rsync, fstrim, etc.) and handles optional features gracefully.

Full Changelog: https://github.com/tsqrdster/Backup_pi/commits/v1.0.0