Hover event for splitter

[lmvco]

Is your feature request related to a problem? Please describe.

Currently, using CSSs, it's possible to change the cursor when the mouse is over the resizer - https://github.com/tomkp/react-split-pane#:~:text=%2C%200)%3B-,cursor,-%3A%20col%2Dresize
However, it would be nice also to trigger an event - resizerMouseOver - in those scenarios (when the mouse is over the resizer)

Describe the solution you'd like

In the same way, we are providing handlers for mouse click/double or touch start/end in the Resizer (here), I am suggesting to add a similar prop for mouse hover so the caller component can have more agility customising the experience