Chrome OS Discover: add strings for the PIN setup module.

This Cl adds strings only.

Bug: 852553
Change-Id: Icc72b2c36a8c25a9a115aed33c555be0cf412e00
Reviewed-on: https://chromium-review.googlesource.com/1197845
Commit-Queue: Alexander Alekseev <alemate@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587831}
8 files changed