[Feat] Add support for InfoWindow headerContent / headerDisabled options

[usefulthink]

Target Use Case

Currently in beta in the Maps JavaScript API, there will be new options for the InfoWindow, finally allowing users to disable the header including the close-button and to specify separate html for the header of the infowindow. These should be supported here as well.

Proposal

Add new props headerContent and headerDisabled for the InfoWindow component. While headerDisabled is just a boolean, headerContent can be arbitrary html, so we should support that via a render-callback, rendering the content into a portal.