Add support for Azure Table Storage

[huydinhle]

Add support for Azure Table Storage to be used as index for store chunks

[khaines]

I've been looking at what an Azure Table storage client would look like and the investigation has lead me to the question "Do we need one?". The reason for this question is two fold:

1. Azure Table Storage's query & filtering syntax does not support operators such as "BeginsWith", which is needed for some of the prefix filtering. While some manual work can be done, this can become very brittle & complex with strings.
2. Cosmos DB supports a Cassandra API interface. This would appear to allow cortex to run on Microsoft Azure using CosmosDB as the backing storage for index (& chunks).

If the core part of the request for Azure tables support is to use cortex on Azure IaaS or AKS, then I don't believe we need to write a completely separate component here. I am currently setting up an AKS POC using CosmosDB to test and see if there are any unexpected errors using the Cassandra storage.

[khaines]

With the AKS POC test run a success, the Cassandra API for Azure Cosmos has been proven to work for storing indexes & chunks. I've also recently added to the master branch support for Blob Storage to store chunks.