should we host devel and stable images?

[cbm755]

• Perhaps in a different image name? (there was some concern about bad publicity)
• or perhaps there is a standard way to deal with dev versions within container images

[cbm755]

Note: that Octave's stable is more like "upcoming release": this is distinct from our releases..

[siko1056]

Sorry for not really getting into this @cbm755 . It might be nice to have. At the moment I do not have the time to work on this. Please feel free to make any changes in this direction.