Remove docutils dependency

[nateprewitt]

Now that we've removed upstream dependencies on botocore to supply docutils, we're able to remove the dependency completely. This should not affect existing users of botocore since the dependency was primarily for help documentation in AWS CLI and local doc generation.

Doc generation should run now without this dependency and if extended usage of the doc suite is needed for some reason, requirements-docs.txt still supplies the original dependency tree. Please note bcdoc is not a public interface and is subject to further change without warning.

This should resolve #900, #933, #1942, #1944, #2120, #2121.

[codecov-commenter]

Codecov Report

Merging #2154 into develop will increase coverage by 5.17%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #2154      +/-   ##
===========================================
+ Coverage    93.11%   98.29%   +5.17%     
===========================================
  Files           60       58       -2     
  Lines        11143    10556     -587     
===========================================
  Hits         10376    10376              
+ Misses         767      180     -587     

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[kyleknap]

Cool. Looks good to me. Just a small comment

[kyleknap]

I think we should remove it from the requirements-docs.txt as well. There is not really a point to keep this around since the file is really only used to help with HTML doc generation and docutils was never actually ever used to generate botocore/boto3 docs.

[nateprewitt]

We actually need this here because older versions of Sphinx have a relatively unbounded dependency on docutils. We'll need to install it until we upgrade Sphinx, so this identifier let's us keep control for now. I'll make a TODO to work on the Sphinx changes in a future PR.

[kyleknap]

Looks good! 🚢