General: Event callbacks pass event to callbacks as expected

[iLLiCiTiT]

Brief description

It seems that event callbacks were broken for all Python 2 hosts because of wrong check of function signature when a method was used.

Description

To find out if arguments should be passed is tried to bound argumets to callback instead of checking the function specs on own. Also added option to pass event as kwarg to callback function (positional arguments have priority).

Additional information

This PR was made because of issues in Publisher tool when combined with Nuke 12.* in PR.

Testing notes:

1. Try event callbacks in Python 2 host where are used for method bounding

[jakubjezek001]

Tested in Nuke New publisher but something is still not clicking as it should. It is showing now workfile isntance and legacy convertor plugin but not the button in instance attributes.

Once I click on any instance it is doing also nothing and this is in terminal.

Traceback (most recent call last):
  File "C:\CODE\__PYPE\OpenPype\openpype\tools\utils\widgets.py", line 77, in mouseReleaseEvent
    self._mouse_release_callback()
  File "C:\CODE\__PYPE\OpenPype\openpype\tools\publisher\widgets\card_view_widgets.py", line 315, in _mouse_release_callback
    self.selected.emit(self._id, self._group_identifier, selection_type)
TypeError: selected(QString,QString) only accepts 2 argument(s), 3 given!

[iLLiCiTiT]

Once I click on any instance it is doing also nothing and this is in terminal.

Issue unrelated to this PR.