Explain name importation and its relevance to securely hosting .bit domains

[JeremyRand]

Name importation is important for securely hosting .bit domains, so it should be explained on the site.

Rough explanation (copied and pasted from an e-mail from me to indolering):

"If you need the ability to change the IP address from a hot wallet, the IP address should be in a dd/ name, which is imported into a d/ name. The d/ name should specify a TLS fingerprint, and should not be in a hot wallet. In the event that the hot wallet is compromised and the dd/ name is hijacked, your website will display a TLS error until you register a new dd/ name, but your .bit domain will not be stolen, and your visitors will not be MITM'ed (unless they're stupid enough to click through the TLS error)."

[phelixbtc]

Should go into the wiki, too.