Rewrite legacy recipes as yml files

[probonopd]

Rewrite all existing non-yml (legacy) Recipe files as .yml files following this documentation. This way, they can serve as examples for how to convert packages into the AppImage format for new contributors and upstream software projects. The legacy Recipe files will then be removed, as they are no longer the recommended way of doing this.

[darealshinji]

Just as a note, the following old recipes are already available in the new .yml format:

arduino
atom
darktable
fbreader
gimp
inkscape
leafpad
lmms
monodevelop
octave
simplescreenrecorder
spotify
travis
wireshark