Changing the domain doesn't necessarily mean I want to change the record

[stuartpb]

If I'm entering a domain that's a new sub-domain when I have a record for the overall site, I might just want to add a record for the new sub-domain. The current UI flow doesn't account for this.

Suggested flow changes/improvements:

• When hitting edit, if the domain doesn't match the profile/record-agnostic suggestion for the domain (ie. the full domain minus a leading "www"), prefill with the full domain.
• If the new domain is a more specific match than the default, present a "Save new" button alongside "Change". (And, if it isn't, "Change" should somehow represent that it implies "create a Use record for this domain" - I need to go back and look at how I drafted the Use record UX spec.)