Add search bar to SearchActivity.

Styling doesn't look exactly right yet but there's a bar.
Creates an ItemDecoration to add a spacer above the first view.

Removes the action bar and replaces it with a SearchView
inside of a CardView.

Remaining work: pixel pushing

Bug: 37477506
Test: make RunSettingsRoboTests
Change-Id: Ibf38c3c2725551bc4cd90e98d0020ec49c2eab2b
Merged-In: I4a0f0c91c51ff5820b61a596520d80a3337c3466