Use Local IPFS Gateway with Model Viewer

[codynhat]

The browser will currently always download assets for Model Viewer from some configurable IPFS gateway. This is because Model Viewer needs to be given a src attribute with the location of the GLB file.

There are cases when loading an asset from a local IPFS node would be better. This may be a better route than using a public gateway if the asset is already stored locally. This could either be done:

1. js-ipfs node is running in browser and has the content. Can be fetched via a service worker running a gateway. See https://github.com/ipfs-examples/js-ipfs-browser-service-worker
2. Some other local IPFS node (Brave, IPFS Desktop, etc) has the content and is running a gateway. This is when ipfs-provider is using an HTTP client

The browser also appears to cache assets using normal HTTP caching. So it is unclear how much benefit this approach would really have.

[codynhat]

Using Helia is now probably the best choice https://github.com/ipfs-shipyard/helia-service-worker-gateway