ncm-gip2: use CAF::FileWriter instead of LC::Check::file

use a sub like
```perl
sub write_encoded
{
    my ($self, $file, $perm, $contents);
    my $fh = CAF::FileWriter->new($file, mode => $perm, log=> $self);
    print $fh encode_utf8($contents);
    return $fh->close();
}
```

and use here like
```perl
my $changes = $self->write_encoded("$etcDir/$file", 0644, $contents);
```