Add plural storage containers

[Tarmil]

The changes in this PR are as follows:

• Storage: add plural add_blob_containers, add_public_containers, add_private_containers, add_file_shares, add_file_shares_with_quota and add_queues (string seq).
• Storage: fix quadratic complexity in add_queues (StorageQueueConfig seq).

I have read the contributing guidelines and have completed the following:

• Tested my code end-to-end against a live Azure subscription.
• Updated the documentation in the docs folder for the affected changes.
• Written unit tests against the modified code that I have made.
• Updated the release notes with a new entry for this PR.
• Checked the coding standards outlined in the contributions guide and ensured my code adheres to them.

If I haven't completed any of the tasks above, I include the reasons why here:

Below is a minimal example configuration that includes the new features, which can be used to deploy to Azure:

let account = storageAccount {
    add_blob_containers [ "blob1"; "blob2" ]
    add_public_containers [ "public1"; "public2" ]
    add_private_containers [ "private1"; "private2" ]
    add_file_shares [ "share1"; "share2" ]
    add_file_shares_with_quota [ "share3"; "share4" ] 1024<Gb>
    add_queues [ "queue1"; "queue2" ]
}

[ninjarobot]

This looks great, thanks for including tests and docs over the changes.

Would it simplify the code to change the various fields in StorageAccountConfig to Set types instead of lists? Then they will remain distinct even as people call these operations multiple times.