Ref https://github.com/sbt/sbt/issues/5665
This implements `--client` option to use `sbt` script as the sbtn runner. The build user can also set the env variable `SBT_NATIVE_CLIENT` to `true`.
The script will attempt to parse `project/build.properties` and use sbtn only when it's sbt 1.4 or above.
This adds a Debian build section that will create
a new .deb file for the sbt script. This includes
a new src/debian and src/debian-gzipped directories
for placing files that will be included in the
distribution on debian.
Initial cut at making debian packages