Replace periodic handlers with event driven disco
Replace periodic handlers with event driven disco

Remove use of periodic consul handlers in the client and just use
goroutines. Consul Discovery is now triggered with a chan instead of
using a timer and deadline to trigger.

Once discovery is complete a chan is ticked so all goroutines waiting
for servers will run.

Should speed up bootstraping and recovery while decreasing spinning on
timers.

dvusboy/nomad,dvusboy/nomad,xytis/nomad,nak3/nomad,achanda/nomad,hashicorp/nomad,novilabs/nomad,Ashald/nomad,diptanu/nomad,hooklift/nomad,barnardb/nomad,jorgemarey/nomad,jorgemarey/nomad,hooklift/nomad,barnardb/nomad,xytis/nomad,hashicorp/nomad,diptanu/nomad,frundh/nomad,dvusboy/nomad,nak3/nomad,burdandrei/nomad,Ashald/nomad,kmalec/nomad,achanda/nomad,hooklift/nomad,Ashald/nomad,frundh/nomad,dvusboy/nomad,barnardb/nomad,novilabs/nomad,achanda/nomad,Ashald/nomad,burdandrei/nomad,achanda/nomad,novilabs/nomad,hashicorp/nomad,dvusboy/nomad,kmalec/nomad,novilabs/nomad,achanda/nomad,dvusboy/nomad,barnardb/nomad,burdandrei/nomad,frundh/nomad,nak3/nomad,burdandrei/nomad,xytis/nomad,novilabs/nomad,kmalec/nomad,kmalec/nomad,achanda/nomad,jorgemarey/nomad,frundh/nomad,nak3/nomad,burdandrei/nomad,xytis/nomad,hashicorp/nomad,achanda/nomad,hashicorp/nomad,frundh/nomad,diptanu/nomad,hooklift/nomad,kmalec/nomad,kmalec/nomad,nak3/nomad,hooklift/nomad,hooklift/nomad,Ashald/nomad,barnardb/nomad,jorgemarey/nomad,hashicorp/nomad,dvusboy/nomad,burdandrei/nomad,frundh/nomad,burdandrei/nomad,barnardb/nomad,jorgemarey/nomad,xytis/nomad,diptanu/nomad,Ashald/nomad,nak3/nomad,diptanu/nomad,frundh/nomad,jorgemarey/nomad,barnardb/nomad,novilabs/nomad,novilabs/nomad,diptanu/nomad,nak3/nomad,xytis/nomad,jorgemarey/nomad,Ashald/nomad,xytis/nomad,kmalec/nomad,hooklift/nomad,diptanu/nomad