chore: encapsulate flask app into superset app

[ofekisr]

SUMMARY

encapsulate the flask app under supersetApp type, then new features can be declared and added to the new type

[codecov]

Codecov Report

Merging #15281 (763cb51) into master (2792ddc) will decrease coverage by 0.15%.
The diff coverage is 70.58%.

❗ Current head 763cb51 differs from pull request most recent head 80fdda6. Consider uploading reports for the commit 80fdda6 to get more accurate results

@@            Coverage Diff             @@
##           master   #15281      +/-   ##
==========================================
- Coverage   77.16%   77.01%   -0.16%     
==========================================
  Files         973      973              
  Lines       50371    50376       +5     
  Branches     6140     6140              
==========================================
- Hits        38871    38798      -73     
- Misses      11296    11374      +78     
  Partials      204      204              

Flag	Coverage Δ
hive	?
mysql	81.66% <70.58%> (-0.01%)	⬇️
postgres	81.68% <70.58%> (-0.01%)	⬇️
python	81.77% <70.58%> (-0.30%)	⬇️
sqlite	81.31% <70.58%> (-0.01%)	⬇️

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Impacted Files	Coverage Δ
superset/initialization/__init__.py	88.05% <67.74%> (-0.25%)	⬇️
superset/app.py	83.33% <100.00%> (+2.08%)	⬆️
superset/db_engines/hive.py	0.00% <0.00%> (-82.15%)	⬇️
superset/db_engine_specs/hive.py	69.20% <0.00%> (-17.21%)	⬇️
superset/views/database/mixins.py	81.03% <0.00%> (-1.73%)	⬇️
superset/db_engine_specs/presto.py	83.36% <0.00%> (-1.06%)	⬇️
superset/db_engine_specs/base.py	87.97% <0.00%> (-0.41%)	⬇️
superset/connectors/sqla/models.py	88.22% <0.00%> (-0.24%)	⬇️
superset/utils/core.py	88.93% <0.00%> (-0.13%)	⬇️

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[amitmiran137]

LGTM!
nice encapsulation

[john-bodley]

@ofekisr could you please provide more context as to why this is needed?

[cwegener]

@ofekisr could you please provide more context as to why this is needed?

It doesn't look like this encapsulation ever ended up being used anywhere. What indeed is the point of having this SupersetApp class?

[cwegener]

@ofekisr could you please provide more context as to why this is needed?

It doesn't look like this encapsulation ever ended up being used anywhere. What indeed is the point of having this SupersetApp class?