404s on deep links with Github Pages

[alukach]

If this application is served on Github Pages, deep links (ie links to anything but the root URL) don't work.

Example

• ✅ http://stac-manager.ds.io/ <- links to root operate correctly
• ❌ http://stac-manager.ds.io/collections <- links to any subpath fail

Possible solution

We may want to consider incorporating a solution utilizing a custom 404.html document, as describe in this repository: https://github.com/rafgraph/spa-github-pages