block/nbd: Use URI parsing code from glib

block/nbd: Use URI parsing code from glib

Since version 2.66, glib has useful URI parsing functions, too.
Use those instead of the QEMU-internal ones to be finally able
to get rid of the latter. The g_uri_get_host() also takes care
of removing the square brackets from IPv6 addresses, so we can
drop that part of the QEMU code now, too.

Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20240418101056.302103-11-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>