Milo switcher: change links and names to developer-facing ones.

* Change all links to point to ci.chromium.org instead of
luci-milo.appspot.com.
* Refer to everything as LUCI UI instead of Milo (internal name).
* Use favicons from Milo as extension icons for consistency.

Bug: 773319
Change-Id: I42de4fe2e206749819d168f0ccf4c2f8f58190b9
Reviewed-on: https://chromium-review.googlesource.com/709466
Reviewed-by: Ryan Tseng <hinoka@chromium.org>
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
13 files changed