Add configuration serialization and deserialization

[djhoese]

This is a port of the work done in dask/dask#6987

It adds a serialize and deserialize function to make it easier to send a config to a remote machine as an environment variable. I also added a convenience Config.serialize which serializes the current Config object.

CC @jhamman who might be interested in this since we've talked about serialization in the past.
Also CC @jacobtomlinson in case he has any opinions.

[codecov]

Codecov Report

Merging #60 (02acff5) into main (0089d00) will increase coverage by 0.07%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #60      +/-   ##
==========================================
+ Coverage   98.11%   98.18%   +0.07%     
==========================================
  Files           6        6              
  Lines         689      717      +28     
==========================================
+ Hits          676      704      +28     
  Misses         13       13              

Flag	Coverage Δ
unittests	98.18% <100.00%> (+0.07%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
donfig/__init__.py	100.00% <100.00%> (ø)
donfig/config_obj.py	95.27% <100.00%> (+0.21%)	⬆️
donfig/tests/test_config.py	100.00% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.