package/zeromq: add websocket option

package/zeromq: add websocket option

websocket support is available since version 4.3.3 and
https://github.com/zeromq/libzmq/commit/9be833493877258af3bc6acdc65565db6674768d
It is enabled if --enable-drafts is passed by the user.

websocket can use libnss or gnutls instead of its builtin SHA1 since
https://github.com/zeromq/libzmq/commit/7296fb5b151920a4a8d272da69196df8ca155aa1

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>