Support initialization from a Redis connection String

[lpellegr]

This client library does not support initializing a client from a connection string or URI. For instance, in an app I am working on, I receive a Redis connection string as input. Due to the lack of support for such input in the client library, I have to parse the String by myself or change the way connection data are passed.

All libraries I know support passing a connection String to initialize a connection to a database. Adding support should be quite easy since the underlying Jedis library that is used supports the use case. If you agree to fix this issue, the main issue is whether you prefer to support a String, a URI, or both as input.

[gkorland]

To avoid duplicating all the Jedis settings we added this construction, that allows you to pass a Jedis pool that is configured the way you want it.

public RedisTimeSeries​(redis.clients.jedis.util.Pool<redis.clients.jedis.Jedis> pool)