Support remove queues, as well as pause all / resume all

[rustworthy]

Addresses #56

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This change is 

[rustworthy]

@jonhoo

I encountered some issues when trying to make Client hold a boxed dyn Connection . Our Reconnect trait mentions Self in the return value of it's only method, making the whole thing not object safe. So introducing a Client which is
a struct with the following shape ...

type Connection = Box<FaktoryConnection>;
struct Client {
  connection: Connection,
  opts: ClientOptions,
 }

... did not work.

I might be missing something though..

Otherwise the PR is ready for review.

[jonhoo]

Would you mind splitting this PR into multiple, one for each logical change? It's a little hard to review the changes when multiple of them are bundled together in this way.

[rustworthy]

Would you mind splitting this PR into multiple, one for each logical change? It's a little hard to review the changes when multiple of them are bundled together in this way.

Sure

[rustworthy]

@jonhoo

Only queue control actions are left in this PR. Please have a look at it once again

[jonhoo]

This looks great, no notes!