[x] Make the async upload endpoint available in the router
[ ] Make a simple JS library to facilitate uploading asynchronously
[x] Update Ecto type to accept IDs from other backends (maybe using a URI-ish? cache://<file id> or store://<file id> -- this potentially could remove the need of the TypeTemplate)
Make a simple JS library to facilitate uploading asynchronouslycache://<file id>
orstore://<file id>
-- this potentially could remove the need of the TypeTemplate)