rpc: getaddednodeinfo missing nodes which are not yet connected

[tuxcanfly]

Right now permanent nodes added via node rpc call might be missing from getaddednodeinfo if they are not yet connected. They are retried in the background but since they don't have an id yet, they can't be disconnected.

We can use connmgr to query permanent nodes and return some id using which it should be possible to disconnect such nodes.

[davecgh]

I'd like to add that this applies to --connect and --addpeer persistent peers added at the config file and/or command line params as well as those dynamically added via RPC later with node or addnode.