schnapps: improve documentation for remote snapshots
Right now configuration there is kind of pilled up in one section. It does not make any difference between protocols and that can be confusing to users (such as schnapps#29 (closed)).
I think that reorganizing it to have dedicated sections for configuration required for specific supported protocol should be made. That is there should be dedicated section for every protocol schnapps support with suggested (example) configuration. It might also make sense to split whole article to multiple articles to make navigation in it easier (adding another subsections might make it rather complicated and long).