The vagrant based tests currently reside in a single project, creating
dozens of tasks to manage starting and stopping the vagrant VM along
with running java and bats tests within each image. This all-in-one
pattern makes parallelizing packaging tests difficult.
This commit rewrites the vagrant testing infrastructure to be
independent of the actual test runners, thus allowing each platform to
be handled in a separate subproject. Additionally, the java and bats
tests are changed to be run through a "destructive" gradle task, which
is run inside the VM. The combination of these will allow
parallelization both locally (through running several VMs at once) as
well as running the destructive tasks in CI machines dedicated to each
platform (thus removing the need for vagrant in CI).