[bitnami/zookeeper] add zookeeper peerType,observer

[bimoQi]

Signed-off-by: bimoQi [email protected]

Description of the change

Add zookeeper peer_type observer mode, Use params ZOO_PEER_TYPE=observer

Benefits

The observer mode of zookeeper can be easily set

Possible drawbacks

Applicable issues

https://github.com/bitnami/bitnami-docker-zookeeper

Additional information

Refer to zookeeper observer documentation https://zookeeper.apache.org/doc/r3.6.3/zookeeperObservers.html