Change click/auxclick/contextment/dblclick event types to PointerEvent?

[NavidZ]

@garykac @travisleithead @BoCupp-Microsoft @patrickhlauke

We've seen some need to additional information for the meta events that are generated for different pointers. Attributes such as pointerType seems to be useful for some web apps as mentioned in this issue file against PointerEvent repository.
So we have two paths:

1. Either add all the attributes required back to the MouseEvent idl.
2. Just change these meta events (i.e. click, auxclick, contextmenu, and dblclick) type to the PointerEvent.

I wonder how ui events folks feel about the second solution. From PointerEvents perspective that seems to be a better long term solution but obviously we need to evaluate the compat impact of that.

[patrickhlauke]

noting that one of the compat issues may be the fact that in Pointer Events, the coordinates are fractional - likely the biggest potential problem, as scripts likely won't expect that