update docker and partial fixes on the notebooks

[fnikolai]

Description

1. Update Dockerfile to mount contrib along with examples
2. Update Dockerfile to include user-defined dependencies (requirements.txt)
3. Fix the dependencies in Docker-Compose
4. Some stylistic changes on the notebooks

Related Issues

Checklist

• Is this code covered by new or existing unit tests or integration tests?
• Did you run make test successfully?
• Do new classes, functions, methods and parameters all have docstrings?
• Were existing docstrings updated, if necessary?
• Was external documentation updated, if necessary?

Additional Notes or Comments

[codecov-commenter]

Codecov Report

Attention: 22 lines in your changes are missing coverage. Please review.

Comparison is base (34830a7) 80.33% compared to head (61d7276) 79.81%.
Report is 129 commits behind head on main.

Files	Patch %	Lines
superduperdb/backends/base/compute.py	68.96%	9 Missing ⚠️
superduperdb/backends/dask/compute.py	85.29%	5 Missing ⚠️
superduperdb/backends/base/query.py	85.71%	3 Missing ⚠️
superduperdb/backends/base/metadata.py	66.66%	2 Missing ⚠️
superduperdb/backends/base/artifact.py	66.66%	1 Missing ⚠️
superduperdb/backends/base/data_backend.py	66.66%	1 Missing ⚠️
superduperdb/backends/ibis/data_backend.py	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1412      +/-   ##
==========================================
- Coverage   80.33%   79.81%   -0.53%     
==========================================
  Files          95      103       +8     
  Lines        6602     7276     +674     
==========================================
+ Hits         5304     5807     +503     
- Misses       1298     1469     +171     

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[blythed]

This will throw an error if requirements.txt doesn't exist. Can't we make this an option?

[fnikolai]

It will complicate everything. It's simpler to assume that requirements.txt will always exist (but will empty).