"Add SSH Key" UI could provide more context and pointers

Currently, the "Add SSH Key" UI in the console looks like this:

I worked out what it wanted by trial and error against its validation logic. It might be nice to provide more proactive clues as to what it wants. For instance:

• The name has to be a valid DNS name, which I'm separately reporting in Omicron since my key names aren't
• The description is helpfully noted as optional, so we're good
• The big mysterious public key box wants an openssh-style public key line

Maybe we could add guidance at the bottom, something like:

Example: ssh-rsa ......
(Link to where to find it on various platforms)

Or better yet, a file upload dialog to save me the trouble of doing cat ~/.ssh/id_rsa.pub | xclip -i and then middle-clicking the text box.

Start at the console's Add SSH Key UI and inspect the existing validation logic to document the accepted name and public-key formats. Decide whether the scoped improvement is inline guidance, platform-specific pointers, or file upload; done means the selected guidance or upload flow is available without trial and error.