can you use the atp file system to show your avatar to external places?
ATP assets are only available in the domain from which they are “pulled”
so in order to travel to other places with your own avatar you always need something like a rented content server? (Amazon S3, Dropbox, a VPS server)
Only until the ATP across domains is fixed. That feature is currently in development.
You can set up your own personal server too. Do not use dropbox, they are hostile to the kind of data transfers caused by HF. Try Digital Ocean.