Don't allow entry of invalid ssh keys

When adding an ssh key, one is inclined to simply paste an openssh-style public key file of the form 

ssh-rsa abcdef1234...fedcba0987654321 somekey_id

into the text field.  The UI accepts this, but when the key is actually provisioned (to ldap, for example), the key will be 

ssh-rsa ssh-rsa abcdef1234...fedcba0987654321 somekey_id comment

I guess in a way this makes sense, as COmanage simply adds the key type and comment the user has provided, but for a user it is a bit unfriendly.

I guess there are several ways around this:

1. make clearer in the UI what the user should enter, exactly
2. reject user input that doesn't adhere to the format COmanage is expecting (the common case can be caught based on a simple regex, I guess)
3. automatically detect the openssl key foramt, and populate/override the key type and comment fields.

From a UI point of view, option 3 would be preferable, I guess.  It could be implemented by a small piece of js, and combined with a server side check for option 2.