Dockerfile: disable pip cache in deployment

[pjonsson]

Tell pip to not write the cache when
in the deployment image.

Also disable the version check on
the remaining uses of pip, this saves
some time since it avoids a HTTP
request on startup.

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📚 Documentation preview 📚: https://datacube-explorer--589.org.readthedocs.build/en/589/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.32%. Comparing base (aa0d9f3) to head (5bbb147).
Report is 25 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #589      +/-   ##
===========================================
+ Coverage    86.29%   86.32%   +0.03%     
===========================================
  Files           26       26              
  Lines         3451     3466      +15     
===========================================
+ Hits          2978     2992      +14     
- Misses         473      474       +1     

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[omad]

Thanks