Suggestion: prompt for "are you sure" when regenerating coldkey keypair

[Jackalgirl]

Currently, people just simply have to know the difference between regen-coldkey and regen-coldkeypub, and they just have to know that it's not safe to do that on a rented server. But people generally don't know this (unless, by some miracle of unicornhood, they have actually read the FAQ channel in the Discord server or docs first).

Recommend that when someone enters btcli w regen-coldkey, there be an intermediate question prompt:

Warning: if you are executing this comment on a rented server, we STRONGLY RECOMMEND that you use regen-coldkeypub instead. Are you SURE you want to use regen-coldkey (Y/n)?

Which, provided that they take a moment to process this, might help protect people against compromises that happen via rented servers.

[Jackalgirl]

Additionally, I think you should do the same thing for btcli w create and btcli w new-coldkey.