Nested Search

## What does this Pull Request Do?

Add Nested Search

## How should this be manually tested?

Run the tests

## Any background context you want to provide?

Example:
```python
{"filter" : { "city.name" : "New York" } }
```

## Any extra info?

@xeBuz 
Roger. Add some test for some invalids queries.
_The world is a dark place_