Allow inst stats to be fetched from onion insts.

[syeopite]

The solution here is quite janky but it's better than nothing. Requires the system to have Curl and Tor installed.

[unixfox]

You could also use a tor2web gateway if you just want to fetch the stats page.
For example for this onion instance: c7hqkpkpemu6e7emz5b4vyz7idjgdvgaaa3dyimmeojqbgpea3xqjoid.onion
I used a tor2web gateway and it works fine: https://c7hqkpkpemu6e7emz5b4vyz7idjgdvgaaa3dyimmeojqbgpea3xqjoid.onion.ws/api/v1/stats