MapLibre pitch map angle for navigation

[spwoodcock]

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

• MapLibre supports a pitch param (so does svelte-maplibre).
• A pitch of 30o can really help users visualise the map for easier navigation.

Describe the solution you'd like

• When the user toggles geolocation, apply a pitch of 30o to the MapLibre element.
• Test if this looks good and assists navigation.