Moved and renamed the scripts to fit with git.
These changes require documentation updates, updates of
the release spreadsheet and the buildbot side.
BUG=chromium:451975
TBR=tandrii@chromium.org
NOTRY=true
LOG=n
Review URL: https://codereview.chromium.org/868473004
Cr-Commit-Position: refs/heads/master@{#26271}
