Add compile-time configuration of mouse sample rate behavior

[nvllsvm]

Adds two CMake variables:

• MS_RATE_DEFAULT: the default mouse sample rate (defualt 100)
• MS_RATE_HOST_CONTROL: whether the host should be allowed to change the mouse sample rate (default ON)

Relates to https://github.com/No0ne/ps2x2pico/issues/1#issuecomment-2016936358