✨ Add metamodeling load tests

[bisgaard-itis]

What do these changes do?

• refactor the performance tests
• update the version of locust we use
• Add a load test which runs the scenario from https://github.com/wvangeit/osparc-pyapi-tests using locust so it is easier to extend to other scenarios in the future.

Related issue/s

How to test

Dev-ops checklist

• No ENV changes or I properly updated ENV (read the instruction)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 64.8%. Comparing base (cafbf96) to head (d337702).
Report is 312 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (cafbf96) and HEAD (d337702). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (cafbf96)	HEAD (d337702)
unittests	1	0

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #6014      +/-   ##
=========================================
- Coverage    84.5%   64.8%   -19.8%     
=========================================
  Files          10     561     +551     
  Lines         214   28482   +28268     
  Branches       25     205     +180     
=========================================
+ Hits          181   18465   +18284     
- Misses         23    9966    +9943     
- Partials       10      51      +41     

Flag	Coverage Δ
integrationtests	64.8% <ø> (?)
unittests	?

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see 571 files with indirect coverage changes

[sanderegg]

cool, and thanks for the update!

[pcrespov]

thx. Left some comments...

[wvangeit]

Looks good to me, thanks.