Add Private Space settings page

This involves:
1. Adding a new page for PS settings under Security & Privacy
2. Integrating the PS safety source with SafetyCenter.

Also, add the capability to create and delete PS from the page.
Creation is temporary to help with prototyping, and will be removed
finally.

Screenshots:
Private Space Entry point in Security & Privacy Settings:
https://screenshot.googleplex.com/4VHxNekjhxZHJwF

Private Space Settings page:
https://screenshot.googleplex.com/3Raw4wuymTHTgtM

Creating Private Space:
https://screenshot.googleplex.com/3dvzAH6V4kQmuYf

Private Space created:
https://screenshot.googleplex.com/Aj7nnF9uuUCa9Q5

Design doc:
https://docs.google.com/document/d/1CdjUjAE84-5ZEPRIfw5KYFjLVHtEZxc_sF0w95su8DA/edit?usp=sharing&resourcekey=0-dAACT9HRexY1IyoxMmkVlw

Bug: 286539356
Bug: 293569406
Test: manual
Test: atest DeletePrivateSpaceControllerTest
Test: atest UseOneLockControllerTest
Test: atest HidePrivateSpaceControllerTest
Change-Id: I9caf8e04e7fb2df36e60f607225e2931988ee692