consumer: make query nsqlookupd timeouts configurable

[guyannanfei25]

when network is not well, 2 seconds may not be able dail success.
Use nsq.Config.DialTimeout to configure this parameter

[mreiferson]

I think this is a good change, thanks for the contribution! However, I don't think we should lean on the existing DialTimeout.

Can we add new LookupdDialTimeout and LookupdRequestTimeout and thread those into the transport instantiation?

[guyannanfei25]

I think DialTimeout means parameter for all connections. Considering lookupds and nsqds are usually in same idc, the network condition is same. Besides even not in same idc, DialTimeout sets a little bigger do no harm for the ones in good network condition. Do we need new LookupdDialTimeout and LookupdRequestTimeout parameters ?

[mreiferson]

My thinking is that if we're going to improve this, might as well do it completely and in an obvious way.

[jehiah]

replaced by #360