Automatic mouse buttons layer activation on trackpoint movement

[manna-harbour]

From https://github.com/alonswartz/trackpoint/blob/master/README.md:

Todo: auto-enable mouse-layer on tp movement

Here is an implementation of automatic mouse buttons layer activation on trackpoint movement: https://github.com/manna-harbour/qmk_firmware/blob/crkbd/keyboards/crkbd/keymaps/manna-harbour/.