[Physical Keybaord] Add keyboard touchpad/Mouse page - part2

screenshot: https://screenshot.googleplex.com/A4yihXmkTTo2nM3.png

Add seperate controllers in page and guard with flag.
Original controller will be disabled if flag is off.

This is part of feature for keyboard setting update.
document: go/new-a11y-touchpad-mouse-page

Bug: 377602364
Test: atest SettingsRoboTests
Flag: com.android.settings.keyboard.keyboard_and_touchpad_a11y_new_page_enabled
Change-Id: I20bf7c65a7f9adc734c7382f23a92d1eb41822f1