Adding "Mobile data" and "Data usage" button in mobile settings.

Grant "READ_NETWORK_USAGE_HISTORY" permission to phone because
"Datat usage" button summary needs it. Settings provides new
intent to open mobile data usage page.

Bug: 62201918
Test: Manual
Change-Id: Ie317109c723f3946ace4d34c743081a7ae046462
Merged-In: Ie317109c723f3946ace4d34c743081a7ae046462