Merge Autofill settings into Account settings.

Autofill settings are removed from Language and Input.

They are now in a new top-level Passwords and Accounts page.

Some polish work is left to match the new design.

Bug: 169455298
Test: manual - check settings page and some search keywords
Test: manual - add work profile and check the above again
Test: make RunSettingsRoboTests
Change-Id: I3981ce73fef63f06a40e61e894481d24284614ba