Refactor documentation and enhance Immich backup system

- Updated README.md to streamline content and improve navigation with a new Quick Navigation section.
- Consolidated detailed Plex backup descriptions into dedicated documentation files.
- Added comprehensive Docker Bootstrap Testing Framework documentation.
- Created Immich backup enhancement summary and migration summary documents.
- Implemented webhook notifications and Backblaze B2 integration in Immich backup scripts.
- Centralized logging for Immich backup operations and updated configuration requirements.
- Restructured Telegram bot project documentation for better clarity and organization.
- Enhanced .gitignore to include environment files and Backblaze CLI tool.
- Updated dotfiles README to reference new testing documentation.

Resolves Documentation review #11.

.gitignore

@@ -18,8 +18,12 @@ _book
 # swap file
 *.swp
 
+# environment files
+.env
+
 # Runtime generated files
 logs/
+immich_backups/*.gz
 # Backup files - ignore most backups but keep current state files
 crontab/crontab-backups/*/archive/
 !crontab/crontab-backups/*/current-crontab.backup
@@ -27,3 +31,7 @@ crontab/crontab-backups/*/archive/
 # Temporary files
 *.tmp
 *.backup
+
+# backblaze cli <https://www.backblaze.com/docs/cloud-storage-command-line-tools>
+#   can be downloaded from <https://github.com/Backblaze/B2_Command_Line_Tool/releases/latest/download/b2-linux>
+immich/b2-linux