👾 fix bug: dump database with utf8mb4 character set

bug fix: return backup_status

change .gitignore

change 'configuration.yml' to 'config.yml'

rename 'config.yaml' to 'config.yml'

complete README.md

rename 'settings' to 'config'

code cleanup

update example_settings.yml

implement container prompt for backup and upgrade

remove main.py

add return types

Do not show "Enable Maintenance Mode" message if already enabled

make a backup before upgrade

outsource backup folder cleanup into function in Container class