Adding elasticache_facts module

Module to get facts from AWS elasticache.

Exemple result :

   <127.0.0.1> REMOTE_MODULE elasticache_facts instance_name=test region=eu-west-1
changed: [54.194.130.20] => {"changed": true, "instance": {"configuration_endpoint": {"address": "YYYYY.euw1.cache.amazonaws.com", "port": 11211}, "engine": "memcached", "id": "test", "instance_type": "cache.t1.micro", "node_endpoints": [{"address": "XXXXX.cache.amazonaws.com", "id": "0001", "port": 11211, "status": "available"}], "status": "available"}, "item": ""}