Adding ExecutionPlan support for graph

[chayim]

syncing with latest redisgraph-py, prior to its deprecation

Pull Request check-list

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

• 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)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Is there an example added to the examples folder (if applicable)?
• Is the changes added to CHANGES file?

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

Description of change

Please provide a description of the change here.

[codecov-commenter]

Codecov Report

Merging #1993 (971ed8f) into master (e6ccc9c) will decrease coverage by 0.09%.
The diff coverage is 82.08%.

@@            Coverage Diff             @@
##           master    #1993      +/-   ##
==========================================
- Coverage   93.07%   92.97%   -0.10%     
==========================================
  Files          77       78       +1     
  Lines       16657    16777     +120     
==========================================
+ Hits        15504    15599      +95     
- Misses       1153     1178      +25     

Impacted Files	Coverage Δ
redis/commands/graph/execution_plan.py	75.25% <75.25%> (ø)
redis/commands/graph/commands.py	85.71% <100.00%> (+2.15%)	⬆️
tests/test_graph.py	90.59% <100.00%> (+0.66%)	⬆️
tests/test_cluster.py	98.29% <0.00%> (-0.13%)	⬇️

---

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 e6ccc9c...971ed8f. Read the comment docs.