First refactoring to provide multiple debian packaging strategies

This is the first refactoring step to provide an additional java-based debian packaging implementation.
Does this look okay from the coding side? @jsuereth , @kardapoltsev , @aparkinson ?

I basically introduced two new task `debianJDebPackaging` and `debianNativePackaging`.
You set the packaging strategy with `packageBin in Debian <<= debianJDebPackaging in Debian`.
Hmm, we may be going over the top with cake :)    I'm *almost* regretting having used it in the first place.  Did this feel like it made things simpler, or just more complicated to find things?