React-map-gl: Permit `padding` in transitions

[harto]

Mapbox GL JS 1.9 added support for padding in camera functions flyTo, jumpTo, etc.: https://github.com/mapbox/mapbox-gl-js/pull/8638.

It would be great if a similar option was made available through this library. Our use case is that we need to adjust the target viewport based on the width of a sidebar.

[Pessimistress]

This is already supported in WebMercatorViewport.fitBounds

[mayteio]

See https://github.com/visgl/react-map-gl/issues/1099#issuecomment-629953112 for a function that returns a new viewport with padding, accounting for edge cases.