Node platform improvements

[tdcosta100]

This PR brings some improvements to the Node platform:

• Allows calling Map.render without an options object (just with a callback function), mapping to the void mbgl::Map::renderStill(StillImageCallback) method
• Implements Map.setSize, which was missing
• Changes the default map size from 256x256 to 512x512 (which is the default size elsewhere, including NodeMap::RenderOptions)

Bonus: a little addition to the code example at README.md when the status code is 204 (empty response).

[acalcutt]

This help with several functions exposed by #871 , like SetCenter, SetZoom, SetBearing, not working because because there was no way to call render without changing the view. I think this is an improvement and consistent with other plaform syntax.

I have worked with @tdcosta100 in testing this and it seems to work as expected, the SetCenter, SetZoom, SetBearing functions can now be used.

Tests have been added that show this syntax works.

[acalcutt]

@tdcosta100 before we merge this can you add a entry to the readme under the 5.2.0 release (we haven't released this yet)

https://github.com/maplibre/maplibre-gl-native/blob/main/platform/node/CHANGELOG.md

[tdcosta100]

Done!