Respect flexible field access pattern in geoip and ip_location processors

[flash1293]

Currently in flexible field access mode, the geoip processor writes such an object:

{
  "geoip": {
    "field": "ip",
    "target_get": "my.field"
  }
}

results in

{
  "my.field": {
     "city": "...",
     "country": "...",
     "location": {
        "lat": "...",
        "lon": "..."
     }
  }
}

This is problematic because we go from dotted to subobject, which means that in subsequent processing steps, e.g. my.field.country can't be accessed anymore.

To align things, in flexible field access mode the geoip processor now writes the individual parts as individual properties:

{
  "my.field.city: "...",
  "my.field.country": "...",
   "my.field.location": {
     "lat": "...",
     "lon": "..."
  }
}

Notice how my.field.location would stay in object notation, since we already know for a fact that this is a geopoint, so it's handled as a "single" field.

The same applies to the ip_location processor.