View / add a constrainResolution option

This introduces a breaking change.

This options replaces the various `constrainResolution` options on interactions
and the `fit` method.

Since constraints are now the responsibility of the View, the fact that intermediary
zoom levels are allowed or not is now set in the view options.

By default, the view resolution is unconstrained.

src/ol/interaction/PinchZoom.js

@@ -10,8 +10,6 @@ import PointerInteraction, {centroid as centroidFromPointers} from './Pointer.js
 /**
  * @typedef {Object} Options
  * @property {number} [duration=400] Animation duration in milliseconds.
- * @property {boolean} [constrainResolution=false] Zoom to the closest integer
- * zoom level after the pinch gesture ends.
  */
 
 
@@ -37,12 +35,6 @@ class PinchZoom extends PointerInteraction {
 
     super(pointerOptions);
 
-    /**
-     * @private
-     * @type {boolean}
-     */
-    this.constrainResolution_ = options.constrainResolution || false;
-
     /**
      * @private
      * @type {import("../coordinate.js").Coordinate}