This adds a `fetch website` config to make it a bit easier
to fetch the Git repo for the new chromium.org website.

Bug: 1260171
Change-Id: I1c147dedf18debf8f24f59989b9ff443e4ddd1bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3263176
Auto-Submit: Dirk Pranke <dpranke@google.com>
Commit-Queue: Anthony Polito <apolito@google.com>
Reviewed-by: Anthony Polito <apolito@google.com>