MousePadPlugin: Add gyro mouse

Summary

This MR adds gyro mouse capability, which allows you to move the cursor of a connected device by simply moving the connected phone. It uses standard Android gyroscope sensors. Mainly aimed at usage with computers attached to very large screens (e.g. TV's), as using the touchpad as-is can feel somewhat unnatural.

While it does attempt pretty much the same thing as !285 (closed), this MR attempts to reduce redundancy as much as possible by simply extending the existing MousePadPlugin instead.

Tested on a Xiaomi Redmi Note 11, on a Samsung A71, and on a laptop running Arch Linux and KDE Plasma 5.27.3

Test Plan

1. Make sure the 'Remote Input' plugin is enabled on the Android device.
2. Make sure the 'Virtual Input' plugin is enabled on the target device.
3. Open Plugin Settings -> Remote Input for the target device.
4. Enable the toggle for Gyro mouse.
5. Exit settings and go to the Remote Input activity for the target device.
6. Try moving the device around in 3D space.
7. Confirm that the mouse pointer moves predictably.