XPlot.Plotly some configuration options are missing

According to the Plotly site to [disable the modebar](https://plot.ly/javascript/configuration-options/#never-display-the-modebar) I have to use following option `{displayModeBar: false}`:

`Plotly.newPlot('myDiv', data, layout, {displayModeBar: false});`

While the [current JS generator](https://github.com/fslaborg/XPlot/blob/1e97f7e397e4d90c81d588791e711872aee2e9a3/src/XPlot.Plotly/Main.fs#L37) doesn't allow me to specify the last parameter.

Currently working around it with an ugly `string.replace`, but would be nice to have the possibility to supply these options in type safe mode.