Create feature kAppStoreRating

Create feature which enables the App Store Rating promo for
eligible users.

Bug: None
Change-Id: Ibe1077bfbf9edc4a71b5b6d1c043f9630e30fc99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3867965


Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Hira Mahmood <hiramahmood@google.com>
Reviewed-by: Benjamin Williams <bwwilliams@google.com>
Cr-Commit-Position: refs/heads/main@{#1042256}