[pulsar-io] Add a Pulsar IO connector for Redis sink

[murong00]

Motivation

This PR provides a built-in Redis sink Connector, in order to cache messages in Redis [key-value] pairs. This will effectively make Redis a caching system, which other applications can access to get the latest value.

Modifications

Add a new sub-module in the pulsar-io module.

Verifying this change

This change can be verified as follows:

• deploy the redis sink connector with configuration file containing the following fields:

configs:
    redisHosts: "localhost:6379"
    redisPassword: "redis@123"
    redisDatabase: "1"
    clientMode: "Standalone"
    operationTimeout: "3000"
    batchSize: "100"

• start a redis instance with auth
• send messages with NotNull key/value in the topic declared when deploying the connector
• check in Redis if the message's key-value pairs have been stored in above database

Documentation

# Submit a Redis Sink
$ bin/pulsar-admin sink create --tenant public --namespace default --name redis-test-sink --sink-type redis --sink-config-file examples/redis-sink.yaml --inputs test_redis
    
# List Sink
$ bin/pulsar-admin sink list --tenant public --namespace default
    
# Get Sink Info
$ bin/pulsar-admin sink get --tenant public --namespace default --name redis-test-sink
    
# Get Sink Status
$ bin/pulsar-admin sink status --tenant public --namespace default --name redis-test-sink
    
# Delete the Redis Sink
$ bin/pulsar-admin sink delete --tenant public --namespace default --name redis-test-sink

[jiazhai]

run java8 tests

[murong00]

run java8 tests

[sijie]

run integration tests

[murong00]

run java8 tests
run integration tests

[murong00]

run java8 tests

[murong00]

run java8 tests

[murong00]

run java8 tests

[murong00]

run cpp tests
run java8 tests