Flicker

Added tab-completion of column names via the [`_ipython_key_completions_` method](https://ipython.readthedocs.io/en/stable/config/integrating.html).

Releasing [version 1.0.0](https://github.com/ankur-gupta/flicker/releases/1.0.0) containing breaking changes.
1. `flicker.FlickerDataFrame` is rewritten to remove unnecessary alias methods
2. `flicker.FlickerColumn` has been added which provides a lot of functionality without verbosity
3. `flicker` now works more recent Python 3.9+ and PySpark 3.4.1+.
4. Test coverage has been increased to [99%](https://app.codecov.io/gh/ankur-gupta/flicker).

* Changed columns argument to names because we need to distinguish between a Column object and the column name
* Documentation (still WIP) is now available at https://flicker.perfectlyrandom.org/

* `df.group()` now returns `FlickerGroupedData` object instead of `pyspark.sql.GroupedData` object
* `df.group().count()` will now return a `FlickerDataFrame` object instead of a `pyspark.sql.DataFrame` object

1. Added new methods `any`, `all`, `get_dtype`.
2. Added pass-through methods `groupby` and `write`.
3. Fixed an issue with `min` and `max` methods. They can now be used for non-float columns.
4. Reduced code repetition which should make it easier to read the source code.
5. Added more doc strings.
6. Added more tests to increase coverage from ~52% to ~61%.
7. Added instructions for contributing.