Add a Python script to synchronize our Github vendor branches with the upstream Chromium repositories.
Add a Python script to synchronize our Github vendor branches with the upstream Chromium repositories.

The script automatically tries to find the appropriate remotes and branches for upstream and downstream
repositories, and will report any inconsistencies and errors.

Note that the script only fetches new commits from upstream and pushes them into our vendor branches,
but it doesn't perform any merge into master.

Merging into master should be performed manually and only after carefully consideration!

kromain/chromium-tools,kromain/chromium-tools,kromain/chromium-tools,kromain/chromium-tools