Added support for MONITOR in clusters

[barshaul]

Pull Request check-list

Please make sure to review and check all of these items:

• [X ] Does $ tox pass with this change (including linting)?
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)?
• [X ] Is the new or changed code fully tested?
• [X ] Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• [X ] Is there an example added to the examples folder (if applicable)?

NOTE: these things are not required to open a PR and can be done
afterwards / while the PR is open.

Description of change

Added support for MONITOR command to RedisCluster
closes #1758

[codecov-commenter]

Codecov Report

Merging #1756 (43a5a8f) into master (12f45ee) will increase coverage by 3.37%.
The diff coverage is 93.20%.

@@            Coverage Diff             @@
##           master    #1756      +/-   ##
==========================================
+ Coverage   90.89%   94.26%   +3.37%     
==========================================
  Files          59       74      +15     
  Lines       14229    15669    +1440     
==========================================
+ Hits        12933    14771    +1838     
+ Misses       1296      898     -398     

Impacted Files	Coverage Δ
redis/commands/core.py	90.05% <ø> (+6.05%)	⬆️
redis/commands/search/querystring.py	0.00% <0.00%> (ø)
redis/utils.py	83.87% <ø> (+6.45%)	⬆️
setup.py	0.00% <0.00%> (ø)
tests/test_cluster.py	98.78% <ø> (+0.32%)	⬆️
tests/test_commands.py	99.38% <ø> (+5.90%)	⬆️
redis/commands/sentinel.py	64.28% <23.07%> (ø)
redis/commands/search/document.py	87.50% <50.00%> (ø)
redis/commands/graph/exceptions.py	66.66% <66.66%> (ø)
redis/commands/search/result.py	97.22% <66.66%> (ø)
... and 73 more

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[chayim]

@barshaul Something appears to be incorrect with your environment. Using this PR as an example there are 84 file changes - many of which are already in master. Can you please have a look at that? A good example is the first file - changes appear for the workflow - which is already in master, and should appear accordingly as a merge.