Github Wiki migration

[tovbinm]

Related issues
GitHub wiki is not versioned.

Describe the proposed solution
Migrate GitHub Wiki to https://readthedocs.org/projects/transmogrifai/ which allows us versioned documentation per release.

The docs from this PR can be viewed here - https://transmogrifai.readthedocs.io/en/mt-docs/

Describe alternatives you've considered
N/A

Additional Context
Changes:

• Removed existing docs from repo
• Moved GitHub Wiki pages into /docs + added configs for Sphinx

[codecov]

Codecov Report

Merging #79 into master will increase coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #79      +/-   ##
==========================================
+ Coverage   85.94%   85.97%   +0.03%     
==========================================
  Files         294      294              
  Lines        9547     9547              
  Branches      337      337              
==========================================
+ Hits         8205     8208       +3     
+ Misses       1342     1339       -3

Impacted Files	Coverage Δ
...om/salesforce/op/utils/spark/OpSparkListener.scala	98.7% <0%> (+1.29%)	⬆️
...es/src/main/scala/com/salesforce/op/OpParams.scala	89.58% <0%> (+4.16%)	⬆️

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[leahmcguire]

LGTM!