Updated heatmap visualizations

[NRauschmayr]

Description of changes:

I updated the heatmap to provide better visualizations for large scale distributed training jobs for instance users can now aggregate metrics per worker node. Before aggregation per worker node was not supported, so the visualization becomes very overwhelming see the following image which shows utilization per GPU and CPU core With the updated heatmap, users can aggregate utilization per worker node like in the following image:

Style and formatting:

I have run pre-commit install to ensure that auto-formatting happens with every commit.

Issue number, if available

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-io]

Codecov Report

Merging #481 (a2d627b) into master (a7c697f) will decrease coverage by 1.49%. The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #481      +/-   ##
==========================================
- Coverage   67.06%   65.57%   -1.50%     
==========================================
  Files         173      163      -10     
  Lines       13280    12917     -363     
==========================================
- Hits         8906     8470     -436     
- Misses       4374     4447      +73     

Impacted Files	Coverage Δ
...mdebug/profiler/analysis/notebook_utils/heatmap.py	0.00% <0.00%> (ø)
smdebug/mxnet/graph.py	25.80% <0.00%> (-32.26%)	:arrow_down:
...profiler/analysis/utils/profiler_data_to_pandas.py	36.07% <0.00%> (-28.77%)	:arrow_down:
smdebug/mxnet/utils.py	59.37% <0.00%> (-28.13%)	:arrow_down:
...ler/analysis/notebook_utils/step_timeline_chart.py	0.00% <0.00%> (-21.32%)	:arrow_down:
smdebug/core/logger.py	70.83% <0.00%> (-12.50%)	:arrow_down:
smdebug/core/tfevent/summary.py	81.35% <0.00%> (-11.87%)	:arrow_down:
smdebug/core/reduction_config.py	88.31% <0.00%> (-7.80%)	:arrow_down:
smdebug/core/utils.py	78.15% <0.00%> (-7.17%)	:arrow_down:
smdebug/core/singleton_utils.py	85.29% <0.00%> (-5.89%)	:arrow_down:
... and 22 more

---

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 a7c697f...a2d627b. Read the comment docs.

[NihalHarish]

We need to add a way to test visualizations going forward; for now I will approve these changes.

[atqy]

Just want to ask, why is the update_data function deleted? What is the alternative to that?