Elastic Search sink fixes

I found a small issue with the disposing of the ES sink so I removed the async stuff. it will still batch submit it to ES, but our tests now shows it disposes nicely (we hooked the ILogger to autofac, but it stopped inside the PeriodicbatchingSink  EmitBatchAsync(events).Wait(); function).

I also updated to a better ES template that is more optimized for serilog. The wiki with all the sinks now has the right link. Without the template it also works btw.