Convert internal variables (selectedObject, draggedObject, ...) into instance variables

[jscastro76]

map declares several variables as internal. It would be very useful to have those variables as part of the map instance.

This is an example from how these variables could be used from a page, for instance, for a button to change the wireframe value of an object, checking first if there's an object selected in the map. Currently you have to keep these variables in the page script side capturing first them from the corresponding events

$('#wireButton').on('click', function () {
	if (map.selectedObject) { //if selectedObject is part of the instance we can do this
		if (map.selectedObject.wireframe) {
			map.selectedObject.wireframe = false;
		} else {
			map.selectedObject.wireframe = true;
		}
	}
	map.repaint = true;
});

The variables to be part of the instance should be:

let selectedObject; //selected object through click
let draggedObject; //dragged object through mousedown + mousemove
let draggedAction; //dragged action to notify frontend
let overedObject; //overed object through mouseover
let overedFeature;//overed state for extrusion layer features
let selectedFeature;//selected state id for extrusion layer features