src/tools: hardlink_packages: Autodetect arch from jam remote repository file

Change-Id: Iccbcdb3105bf7762259493b9852446a3c83fbd2f

src/tools: hardlink_packages: LooseVersion was deprecated

Change-Id: I3711e76d8357651aa6b400a1c9579d40aa64c558

tools/hardlink_packages: Trigger an error if there are duplicate package entries.

This would have caught a user error on my part in the last build-packages
update.

hardlink_packages: Use distutils to compare versions.

hardlink_packages: Fix arguments check.

Thanks Jessica for the review!

hardlink_packages: Use subprocess instead of os to check for package_repo.

tools/hardlink_packages: Check that the package_repo command exists.

hardlink_packages: Clarify packages directories in helptext.

tools: Add a new hardlink_packages.py script.

This is essentially the replacement for "jam upload-packages" --
it goes through a directory of packages (intended to be one made by
buildmaster), picks the packages out of it that are in the repository
file passed to it, and then hardlinks them to a second directory
as well as updates the repository file and creates a package_repo.

This is what was used to mass-modify the repository files which
will be updated in the next commit.