Add data processing scripts for chrome-speed-metrics

Add data processing scripts for chrome-speed-metrics

We create a new directory chrome_speed_metrics under experimental. It should
hold all the experimental code by the chrome speed metrics team. Previously, the
experimental code went to the csm fork
(https://github.com/catapult-project/catapult-csm), but we decided it was better
to use experimental directories and branches on the main repository to make it
easier to everyone to keep up with how catapult code was being used.

[dproy, 2017-09-19 04:58:38]

The CQ bit was checked by dproy@chromium.org

[commit-bot: I haz the power, 2017-09-19 04:58:49]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-09-19 04:58:50]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-09-19 04:58:53]

No L-G-T-M from a valid reviewer yet.
CQ run can only be started once the patch has received an L-G-T-M from a full
committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,_not_ a
full super star committer.
Committers are members of the group "project-catapult-committers".
Note that this has nothing to do with OWNERS files.