Improvements for choosing community adders

[benmccann]

It's a bit surprising that --community only works with add and not create

If you're using --community without specifying any args, I'd also expect it to ask you about the official adders still in addition to showing you the community adders

[AdrianGonz97]

this could be resolved if we go with the mode-switching approach described here: #47 (comment)

[benmccann]

Oh yeah, that would work. If we do that, it would be nice to display the community warning on the choosing screen so you know the risk before making any selection.