Proposal for Calendar

**Enhancement**

I think the month names in Calendar might be an overhead.
In my own widgets I am using a fallback for the `renderMonthLabel` if `Intl` is available

```
function renderMonthLabel(month: number, year: number) {
let { monthNames, renderMonthLabel } = properties();
if (!monthNames && !renderMonthLabel) {
const d = new Date(Date.UTC(year, month, 1, 3, 0, 0));
return new Intl.DateTimeFormat('en-US', {month: 'long'}).format(d)
}
// ...
}
This returns the localised label for a month.
But not sure about i18n …