Implement setSelectHandler() in model view

[#46394205]

Custom select handler will be called when select action is finished
with (x, y, w, h) arguments:
- x - x coordinate of lower left selection corner (in model units),
- y - y coordinate of lower left selection corner (in model units),
- width  - width of selection rectangle (in model units),
- height - height of selection rectangle (in model units).
Add styling of extent area visible while selecting objects

[#46394205]
Provide onSelect function in Scripting API

[#46394205]