Remove a bunch of unused webkitpy code.

This patch removes a bunch of webkit-patch steps and related code that was primarily concerned w/ interacting w/ Bugzilla and/or other WebKit-based ports. Among the things/files removed: the Checkout module, the DeprecatedPort module, and a bunch of steps.

This patch also promotes all the remaining webkit-patch commands that are meant to be run by the user to the main 'webkit patch help' list. Now 'help --all-commands' lists the main commands plus the internal commands like rebaseline-test-internal.

In theory, no one was using any of this stuff so it should be safe to remove. I guess we'll see :).

BUG=
R=ojan@chromium.org

Review URL: https://codereview.chromium.org/27055003

git-svn-id: svn://svn.chromium.org/blink/trunk@159595 bbb929c8-8fbe-4397-9dbb-9b2b20218538