Move oauth2 config from skiaalerts.com to alerts.skia.org.
Move oauth2 config from skiaalerts.com to alerts.skia.org.

BUG=skia:
TBR=borenet

Review URL: https://codereview.chromium.org/866013002

Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot