EFA->new: deprecate efa_url in favour of service

=item my $status = Travel::Status::DE::EFA->new(I<%opt>)

Requests the departures as specified by I<opts> and returns a new

Travel::Status::DE::EFA object.  B<efa_url> and B<name> are

Travel::Status::DE::EFA object.  B<service> and B<name> are

mandatory.  Dies if the wrong I<opts> were passed.

Arguments:

=over

=item B<efa_url> => I<url>

=item B<service> => I<name>

URL to the EFA service. See C<< efa-m --list >> for known URLs.

If you found a URL not listed there, please notify

EFA service. See C<< efa-m --list >> for known services.

If you found a service not listed there, please notify

E<lt>derf+efa@finalrewind.orgE<gt>.

=item B<place> => I<place>