Docker-related scripts for Impala

test-with-docker.py runs the Impala build and tests inside of Docker containers, parallelizing the test execution across test suites. See that file for more details.

This also contains infrastructure to build impala_base, catalogd, ``statestored,impalad_coordinator,impalad_executorandimpalad_coord_exec` container images from the output of an Impala build. The containers can be built via the CMake target docker_images. See CMakeLists.txt for the build targets.