Moving the EA filter query to request URL instead of building it on t…

[chinmayb]

…he payload body

* Currently the EA filters are passed as api payload, this is creating
  problem when the obj is empty and ea is requested in GET call. Hence
  moving it as URL parameter.

  `objJSON = append(append(objJSON[:len(objJSON)-1], byte(',')), eaSearchJSON[1:]...)`
  The above objJSON fails to get unmarshalled when objJSON is not having any payload apart from easearch.  Empty check becomes tedious for the generic obj.  

* Add Get A record call