We added the SSH key notice to the repository form to match something we

had done for RBCommons, but did so in a way that wasn't extensible for

cases such as when the create SSH key link is different. This change

moves it out into its own template so we can replace it if we want.
This also fixes the error notice for when a hosting service account was

linked to use the form variable instead of adminform.

Verified that the SSH key notice still looked correct in the repository

form.