Add noop sink implementation

[brunoluiz]

In case a service needs to run with writing operations disabled temporarily, a noop:// sink implementation would be nice.

This is would be specially useful in case a consumer wants to rebuild its internal state without triggering any integration.

[mjgarton]

When you say "temporarily" do you mean for the lifetime of the sink? I think you do but I'm just clarifying.

[brunoluiz]

The temporarily would be until a specific internal state is restored, for example

[nick-jones]

Resolved by #90