Remove duplicates when fetching the comments, the cache entries

[andrea-smiesna]

Prerequisite #15

An index that leverages data types in Redis was implemented for the comments and another index was implemented for the search property in each cache entry.
The comments and the entries are fetched from the Redis Cache (using the Redis Search) in 2 different API calls to Redis cache.

Find a way how to make it in just one call:

1. merge the indexes if possible/
2. filter out the duplicate values (entries) which are the result of the 2 searches