Splitting documentation for read the docs

[chayim]

This is the beginning of improvements to documentation, it can be thought of part of #1744

closes #1746

[codecov-commenter]

Codecov Report

Merging #1743 (cf375f8) into master (393cd62) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1743   +/-   ##
=======================================
  Coverage   62.34%   62.34%           
=======================================
  Files          59       59           
  Lines       14249    14249           
=======================================
  Hits         8883     8883           
  Misses       5366     5366           

Impacted Files	Coverage Δ
redis/commands/timeseries/commands.py	0.00% <ø> (ø)
tests/test_cluster.py	98.60% <0.00%> (ø)

---

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 393cd62...cf375f8. Read the comment docs.