Add minimalism illustrations to the lock screen notifications

settings page

Add static version minimalism illustrations to the lock screen
notifications settings page. We still need to replace the icons.

In the final version, illustrations will combine the light and dark
versions into a single file. The current status is a middle stage
stands for team fooding. The final version illustrations will also be
animations instead of static.

Bug: 367455695
Bug: 383778222
Flag: com.android.server.notification.notification_lock_screen_settings
Test: manual
Change-Id: I63c0452de60ce1aa94c7b414cb6e81dd98c5f361