Date / time picker component (calendar)

[spwoodcock]

Is your feature request related to a problem? Please describe.

• A standardised date / time picker would be useful across multiple tools.

Describe the solution you'd like

• Date / time picker component with options.
• Details of a work in progress picker that got closed: added sl-date-picker component shoelace-style/shoelace#486
• There is a calendar branch https://github.com/shoelace-style/shoelace/tree/calendar that the maintainer was working on.

We should probably take inspiration from both and create our own.

Describe alternatives you've considered

• Waiting for an sl-calendar component, although I feel this may be made a premium backer feature in Web Awesome.
• It is possible to use the native browser date picker using <sl-input type="date">, but this component would have nicer UX (https://shoelace.style/components/input#input-types)