lapin Automatic reconnection on network failure

Now that we have the topology API, here are the steps required towards automatic reconnection:

[x] add an Option<Consumer> to the wrapped basic_consume, set it to None from the public wrapper, store the Option in the state and use it to restore everything in the given Consumer if we got Some.
[x] introduce an InternalTopology that stores Connection/Channel/Consumer objects alongside the topology items
[x] Add some conversion between InternalTopology and Topology; dropping the associated items
[x] change topology methods to return the Internaltopology, and make the current one use that and convert to public Topology.
[x] in the same way, introduce some restore_internal, make restore use it, and pass the Options stored in the InternalTopology to basic_consume and friends
[x] hook up basic get in InternalTopology + restore_internal
[ ] add an Option<Channel> to the channel creation to share internals with the Channel we want to restore, set it to None, but use it when finalizing if it's Some.
[ ] add an Option<InternalTopology> set to None to the connection process, and use it when it's some to restore_internal
[ ] detect network failure from the event loop, and instead of bubbling it up, call topology_internal, reinitiate connection with Some(InternalTopology)