Adding a KPS counter

[ItsShamed]

It would be cool to have that in lazer as a skinnable component like the pp counter and also useful for some streamers so that they do not rely too much on third-party software. it should look like this:

kps_showcase.mp4

So yeah, the implementation is already done, this is just to ask if it's okay for me to open a PR for it.

[peppy]

It's fine to open a full request for this. Note that it should handle all rulesets hopefully (with a single code path through depending on UserInputManager or the likes), but we can go through this in the pull request if it's not already the case.