v0.1.1-preview8: Context first: build subcommand: OpenJDK

Container first CLI version. Runs build, exec and run in a container.

• OpenJDK build pack fixes: downloading and managing the infinite version "table" 😏

• Build packs code cleanup: fixes to how it downloads and manages PATH

• Checks consistently for sane environment variables settings in the YAML

• Regression: -exec-prefix flag for build is back and running

• Checks all docker mounts, if it doesn't exist locally, give up

• workspace has subcommands that helps manage auto created $HOME/.yourbase/workspace/ dirs

• Regression: build actually searches and uses build target names defined in the YAML

• Timings for Docker container stand up and tools installations

• Container workdir should be set to a default

• Chore: dep Narwhal v0.5.2