Allow pre-processing of blueprint asset paths

[ewmb7701]

This is a feature request.

I have a workspace with a few Bevy apps using bevy_web_asset and a web server so that I can share assets between those Bevy apps. I have run into a snag with this setup: Blenvy loads blueprints from the assets folder of the current Bevy app.

I would like some way to pre-process blueprint asset paths, so that I can change the asset path to a url. Ideally this would be a hook function on the plugin configuration.