Parse ANSI colors

The `journalctl` output contains ANSI color codes for warnings and errors, these could be tourned into displayable [Pango markup](https://developer.gnome.org/pygtk/stable/pango-markup-language.html) using e.g. a modified [ansi2html](https://github.com/ralphbean/ansi2html/blob/develop/ansi2html/converter.py)