Enable programmatic focus of a specific layer's features on the map

[prushforth]

the HTMLLayerElement.focus() implementation should either focus the layer in the layer control, or focus the first or next element in the layer, without moving the map. We should figure out what the correct behaviour is

In any case, I think it should not be the layer control since a "layer" refers to the container (of features etc.) on the map itself, separate from the layer control?

Another option to consider is to enable programmatic focus (tabindex="-1") on the <div class="mapml-layer ..."> (this would make even more sense if each of those layer elements also had an accessible name: #579). One use case for that can be found in https://maps4html.org/experiments/screenreader/closest-restaurants/: after the "Restaurants" button has been pressed AT/keyboard users could/should be directed (have focus delegated) to the relevant features?

Originally posted by @Malvoz in #587 (comment)

[prushforth]

This is implemented for <map-feature> with the focus() method. The layer-.focus() method is renamed to layer-.zoomTo()