Tracker: Website polish

[kylebarron]

Some of these will need to be done in the ocular-theme directly.

• Fix mobile layout (Ocular). Currently subpar:
  

• Loading spinner for examples. Would be helpful to have a Deck-level isLoading prop

• Support GIFs as image thumbnails on the Examples gallery page (Ocular change) and use a GIF for the ImageCollection animation thumbnail.

• Add a helper function that can cut Image and ImageBitmap. Or add note to ImageCollection example that it won’t show up on Safari/iOS devices.

• Add image/GIF behind “earthengine-layers” on homepage, so that it's visible without a login needed.

• change pointerEvents on infobox to allow selection. Currently you can click links but can't select text.

• Example subtitles should be more left-aligned:

  

• Blue labels on published site (only shows for me in Incognito mode):

  

  Also shows up in loaders.gl, so I think this is an Ocular fix:

  

• Python syntax highlighting doesn't highlight comments.

  

  We're using Prism JS, but the standard Prism highlighter does highlight comments: