request help: how to use apisix with zookeeper service discovery

[ChaoYang-OPS]

Issue description

Environment

• apisix version (cmd: apisix version):
• OS: (cmd: uname -a)
• OpenResty / Nginx version: (cmd: nginx -V or openresty -V)

[spacewander]

zookeeper service discovery is unsupported yet.
But you can add it. You can take the eureka support (https://github.com/apache/apisix/blob/master/apisix/discovery/eureka.lua) as an example. PR is welcome!

[youlianyiran]

hope support zookeeper service discovery for dubbo

[membphis]

hope support zookeeper service discovery for dubbo

would like to contribute this feature? @youlianyiran

[spacewander]

Note that dubbo's zookeeper service discovery has some special dubbo relative logic.

[spacewander]

Solved by #6751