Make dask an optional dependency

[tamargrey]

• Allows users to download woodwork with dask using pip install woodwork[dask]
• Closes Make Dask an optional depedency #308
• Closes Add import_or_none to optionally import Dask #344

todo:

• Fix whatever the issue is with coverage this adds
• Handle conda install
• Add tests with and without dask to circleci config??

[codecov]

Codecov Report

Merging #357 (b0c79b0) into main (e4435e9) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main      #357   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           29        29           
  Lines         3320      3342   +22     
=========================================
+ Hits          3320      3342   +22     

Impacted Files	Coverage Δ
woodwork/data_column.py	100.00% <100.00%> (ø)
woodwork/data_table.py	100.00% <100.00%> (ø)
woodwork/deserialize.py	100.00% <100.00%> (ø)
woodwork/serialize.py	100.00% <100.00%> (ø)
woodwork/tests/conftest.py	100.00% <100.00%> (ø)
woodwork/tests/data_column/conftest.py	100.00% <100.00%> (ø)
woodwork/tests/data_column/test_data_column.py	100.00% <100.00%> (ø)
woodwork/tests/data_table/test_datatable.py	100.00% <100.00%> (ø)
woodwork/tests/data_table/test_serialization.py	100.00% <100.00%> (ø)
woodwork/tests/test_utils.py	100.00% <100.00%> (ø)
... and 2 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e4435e9...b0c79b0. Read the comment docs.

[tamargrey]

New circleci test structure looks like (where the optional tests get both unit testing and lint testing, and the minimal tests just get the unit testing)

[thehomebrewnerd]

I think in the CircleCI config we may be running codecov block twice (starting with the when condition on line 86). If I'm reading this right, this block will run any time we are running python 3.6. We should only run this when we have the optional libraries installed and python 3.6. I'm not great with digesting config.yml files, so I might be wrong.

Maybe take a look at what featuretools does for comparison:
https://github.com/FeatureLabs/featuretools/blob/c51ef4e2944bb754de5696833b480b316916202a/.circleci/config.yml#L170-L173

Other than that, I only noticed a couple other relatively minor things.

[gsheni]

The reason for the quotes is because some shells (like zsh) use square brackets for pattern matching while other shells (like bash) don't. Adding quotes makes it work for all shells.

[gsheni]

Minor things. Looks good overall.

[gsheni]

lgtm

Fixes have been addressed