Add viewer height to options configuration

[adamjarling]

Description

We should allow Viewer consuming applications to specify what height (in pixels), they'd prefer to render the OpenSeadragonViewer.

Done looks like

• [x] height is added to the options prop object on root component.

const options = {
    showDropdown: true,
    ...
    height: 800 // default
  };

  return (
    <OpenSeadragonViewer manifestUrl={manifestUrl} options={options} />
  );