fix: as_of, event_range, join, default behavior and duplicates… (#764)

* Bug fixed - as_of, event_range, join, default behavior and duplicates and tests

Bugs:
1. as_of was not working properly on deleted events
2. Same event_time_range
3. Join was not working when including feature names
4. Default sql was returning only most recent, whereas it should all excluding duplicates
5. Include duplicates was not return all non-deleted data
6. instanceof(dataframe) case was also applied to non-df cases while join
7. Include column was returning unnecessary columns.

* Fix on pylint error

* Fix on include_duplicated_records for panda data frames

* Fix format issue for black

* Bug fixed related to line break

* Bug fix related to dataframe and inclde_deleted_record and include_duplicated_record

* Addressed comments and code refactored

* changed to_csv to to_csv_file and added error messages for query limit and recent record limit

* Revert a change which was not intended

* Resolved the leak of feature group deletion in integration test

Author: mizanfiu