Add acceleration to remote input cursor

Summary:
This patch adds cursor acceleration to KDEConnect's remote input plugin. The cursor movement is now scaled down if the movement is slow, and scaled up if the movement is fast.
The acceleration is implemented on the android side. An additional setting was added to the android app's Remote Control plugin preferences, allowing the user to choose the strength of the acceleration, or to disable the acceleration completely.

Test Plan:
After installing this revision on your android device, go to the remote input page and start using the mousepad. Cursor acceleration should be enabled by default.
Check if the cursor acceleration is intuitive and easy to use. Also, try tweaking the acceleration in the Remote input settings in the Plugin settings menu.

Reviewers: KDE Connect, albertvaka

Reviewed By: KDE Connect, albertvaka

Subscribers: albertvaka, kdeconnect

Tags: KDE Connect

Differential Revision: https://phabricator.kde.org/D14720