Add acceleration slider, like sensitivity

Many games already have this and it allows for easier and more diverse ways to play. Gamers using a low sensitivity mouse need faster movements to look around a bigger distance faster. The game already has a sensitivity slider, but acceleration is an important variable, and an option to adjust acceleration is needed in order to allow the whole Minecraft community to enjoy the game.

In the 1.13 update, acceleration got altered in a LWJGL update that went with the update, which made acceleration a lot slower after that. I think this got fixed in 1.14.3. this bug report about it describes the problem: https://bugs.mojang.com/browse/MC-121381

Even though this problem was fixed, an acceleration slider would be a good addition to help people play more effectively.