Optionally set max zoom level in zoomToVectors() and zoomToLayer() methods

[mstenta]

When using the instance.zoomToVectors() and instance.zoomToLayer() methods, there is currently no control over the maximum zoom level. When the vector/layer contains a single point this results in a zoom that is far too close to be useful, forcing the user to manually zoom out to see where they are. This isn't as much of an issue with line/polygon geometries, which are more common.

[paul121]

This is related to #95, although slightly different. Being able to configure both the padding and maxZoom of the fit options would be wonderful!

farmOS-map/src/instance/methods/zoom.js

Lines 20 to 25 in 777758f

	const fitOptions = {
	size: this.map.getSize(),
	padding: [20, 20, 20, 20],
	maxZoom: 20,
	};
	this.map.getView().fit(extent, fitOptions);