rpcproxy is refactored into serverlist which prioritizes good servers
over servers in a remote DC or who have had a failure.

Registration, heartbeating, and alloc status updating will retry faster
when new servers are discovered.

Consul discovery will be retried more quickly when no servers are
available (eg on startup or an outage).

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.

Test asserted endpoint appendend servers, but the new/desired behavior
is for the endpoint to set/overwrite servers.

Also fix log line formatting

It's better to just let goroutines fallback to their longer retry
intervals then try to be clever here.