Removed 'Register' step from navbar

Now to access this step the user must be authenticated and in need to
update its main data

Signed-off-by: Carlos Oliveira <carlospecter@gmail.com>
Set email to be read-only field

Email is a read-only field so that user won't change it in the
'Register' step

Signed-off-by: Carlos Oliveira <carlospecter@gmail.com>