For Odin!

New

• Added Italian translation (thanks to @albanobattistella).
• Added Flatpak manifest for releasing for elementary OS 6.
• Added dark mode system support.

Changes

• Updated application to use libhandy-1 to comply with elementary OS HIG recommendations.
• Updated gtksourceview from 3 to 4.

Bug Fixes

• Fixed random case transform functionality.
• Fixed determination of camel case in text string.
• Fixed warning messages when non-existent files are attempted to be opened.