Travis CI will timeout if there is no activity printed to stdout or
stderr for 10 minutes. Running our mvn commands with --quiet option may
hit this limit for any number of reasons (more code, network
conditions). To avoid this, we remove --quiet and adjust some other
Maven configuration options.

One, specifically, is the cached .m2/repository directory. We bind this
to a non-user home location due to the -u binding found in
run-in-docker.sh. We then provide a settings.xml and CLI option to tell
maven where to look for our cached repository directory. This should
allow both users and CI to run the script in a consistent way, but most
importantly should allow Travis to continue to cache artifacts across
builds.