Dexfile: Dockerfile superset with composition

[ep0ll]

I built Dexfile, a buildkit frontend that support composition of Dockerfiles. I noticed that your project has massive Dockerfiles and I believe by composition it becomes easier to maintain.

[potiuk]

Please - do not advertise your tools in this way. If you want to make PR to improve things - do it - but be aware that community needs to have good justification (on devlist) for new tools used.