Support for RFC-2326 "Colon-Formatted" Media Fragments

[markpbaggett]

Hello, in our manifests, we use RFC-2326 "colon-formatted" media fragments on ranges that look like this:

{
  "type": "Range",
  "id": "https:\/\/digital.lib.utk.edu\/notdereferenceable\/assemble\/manifest\/rfta\/8\/range\/places_mentioned\/5",
  "label": {
    "en": [
      "Parkway (US-321\/US 441 S)"
    ]
  },
  "items": [
    {
      "type": "Canvas",
      "id": "https:\/\/digital.lib.utk.edu\/notdereferenceable\/assemble\/manifest\/rfta\/8\/canvas\/0#t=00:28:03,00:32:01"
    }
  ]
}

It seems that iiif-av-component only supports "seconds notation", but I'm wondering if it would be relatively easy to support colon notation as well.