Add es package

Looking for some feedback on this approach to talking to ES.
I'd prefer it if these exported functions were couched in higher level terms. I'm not really sure that we want callers to need to know the details of the elastic search name space - this package should be hiding that, I think.

There are possible reasons that might not be a good idea though, but my inclination would be to unexport this and the Delete method and create entry points that represent the operations that we will actually want to use.