Added Wifi Assistant Card

+ Show Wi-Fi Assistant card above network list that scroll under the action bar with the rest of the list
+ Display a promo image and text
+ Clicking "Setup" should link to the selected Wi-Fi assistant app (must be open to 3rd parties)
+ Touching "No, Thanks" should snooze this card for 30 days / 2nd time 90 / 3rd time 180 days / then forever

Bug: 15703202

Change-Id: If74101bea630246c6bda2de3ed79fee72eca4c0c