Test bokeh plot performance with large CSV datasets

[BenjaminCharmes]

Closes #1261

Add some fake csv data with N points (N=1k, 100k, 500k) to see how our default bokeh plots scale

It seems that at 1M, the test is already blocked by MAX_CONTENT_LENGTH (/pydatalab/src/pydatalab/config.py):

    MAX_CONTENT_LENGTH: int = Field(
        10 * 1000**3,
        description=r"""Direct mapping to the equivalent Flask setting. In practice, limits the file size that can be uploaded.
Defaults to 10 GB to avoid filling the tmp directory of a server.

Warning: this value will overwrite any other values passed to `FLASK_MAX_CONTENT_LENGTH` but is included here to clarify
its importance when deploying a datalab instance.""",
    )

(And 1B without the limit makes me crash locally)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.30%. Comparing base (d7f5b80) to head (642ba0b).
Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1268      +/-   ##
==========================================
+ Coverage   74.28%   75.30%   +1.02%     
==========================================
  Files          66       66              
  Lines        4487     4487              
==========================================
+ Hits         3333     3379      +46     
+ Misses       1154     1108      -46     

see 5 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[cypress]

datalab    Run #3551

Run Properties:   Passed #3551  •  180a0f6475 ℹ️: Merge 642ba0b5a19ab1f0c1c310938e121ea181142aec into d7f5b8027f62b048bb5e22328acf...

Project	datalab
Branch Review	bc/stress-testing
Run status	Passed #3551
Run duration	07m 45s
Commit	180a0f6475 ℹ️: Merge 642ba0b5a19ab1f0c1c310938e121ea181142aec into d7f5b8027f62b048bb5e22328acf...
Committer	Ben Charmes
View all properties for this run ↗︎

---

Test results
Failures	0
Flaky	0
Pending	0
Skipped	0
Passing	504
View all changes introduced in this branch ↗︎