Update test bots to use cosmos DB

[gabog]

We use MemoryStorage in most of our unit tests in the product and I think it may be better to use cosmosDB for state for end to end testing. It will help us catch serialization and other storage related issues that we don't normally see in our tests based on MemoryStorage (it happened in the past).

[mrivera-ms]

@gabog, would it be good to add a few CosmosDb scenarios instead of updating all existing tests? I have concerns about the time that will take to run all tests if make this change.

[gabog]

Can we use an existing cosmosDB instance so we don't have to wait for the resource to be provisioned? All the cosmosDB serialization issues have been addressed as far as we know and I was hoping the functional tests may help us catch new ones that we may introduce in the future.