TouchpadInputMapper: Add gesture property provider

Gesture properties are configurable parameters used by the gestures
library [0]. These will be used for per-device tuning and to implement
various touchpad settings. The property provider gives Android an
interface with which to get and set property values.

[0]: https://chromium.googlesource.com/chromiumos/platform/gestures/+/refs/heads/main/docs/gesture_properties.md

Bug: 251196347
Test: atest inputflinger_tests
Test: on device with some hacky test code
Change-Id: I7723dcbabf29e13c8ab0907c71e5dd1faa766b45