Add Ballerina Redis client (#2682)

This PR adds information on the Official Redis client library for [Ballerina](https://ballerina.io/). This client comes with the support for Redis clusters, connection pooling and secure connections OOTB.

## References 
- Ballerina Redis Client Package: https://central.ballerina.io/ballerinax/redis/latest
- Source Repository: https://github.com/ballerina-platform/module-ballerinax-redis
- Client Specification Documentation: https://github.com/ballerina-platform/module-ballerinax-redis/blob/master/docs/spec/spec.md
- Ballerina Programming Language Homepage: https://ballerina.io/

Author: NipunaRanasinghe

clients/ballerina/github.com/redis/ballerinax-redis.json

@@ -0,0 +1,7 @@
+{
+    "name": "ballerinax-redis",
+    "description": "Official Redis client for Ballerina language with the support for Redis clusters, connection pooling and secure connections.",
+    "homepage": "https://central.ballerina.io/ballerinax/redis/latest",
+    "repository": "https://github.com/ballerina-platform/module-ballerinax-redis",
+    "recommended": true
+}