feat(ui5-suggestion-item): enable mouseover|out events

[ilhan007]

The user can now bind for mouseover and mouseout events on the ui5-suggestion-item elements and perform some other action. For example: opening another popover, pointing to particular suggestion, when hovered.

FIXES: #1768

<ui5-input id="inputPreview" show-suggestions>
	<ui5-suggestion-item class="suggestionItem" text="Cozy"></ui5-suggestion-item>
	<ui5-suggestion-item class="suggestionItem" text="Compact"></ui5-suggestion-item>
         ...
</ui5-input>

[].slice.call(document.querySelectorAll(".suggestionItem")).forEach(function(el) {
		suggestion.addEventListener("mouseover", function (event) {
			const targetRef = event.detail.targetRef;
			popover.openBy(targetRef, true /* prevent initial focus */); // open popover
		});
			
		suggestion.addEventListener("mouseout", function (event) {
			popover.close(false, true, true); // close popover
		});
});