This is based off the svn tarball bootstrap script in gclient_scm.py
Also included is a new command to create a new zarchive/zipball.

BUG=261741

Review URL: https://codereview.chromium.org/220423002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@261002 0039d316-1c4b-4281-b951-d872f2087c98