idoverrideuser-add: allow adding ssh key in web ui
    
    CLI already allows to pass public SSH key when creating an ID override
    for a user. Web UI allows to add public SSH keys after the ID override
    was created.
    
    Add SSH key field to allow passing public SSH key in one go when
    creating an ID override for a user.
    
    Fixes: https://pagure.io/freeipa/issue/7519
    Reviewed-By: Christian Heimes <cheimes@redhat.com>