Fix Docker image for debugging.

[SpacemanPaul]

Recent docker image changes broke debugging. This fixes it.

Changes:

1. Call apt-get upgrade -y: not strictly necessary, but seems like a good idea.
2. Change /code directory to /src. This is the important one. pydevd imports stuff from the standard library code which the /code directory hides. Required some tweaks to GHAs.
3. Update to pydevd for most recent version of pycharm.
4. Other misc cleanup.
5. Remove pipdeptree as a dev dependency. I can't remember why we needed it and it has pip version dependencies that cause issues because we can't upgrade the Debian-controlled pip.

This has been holding up OWS progress for ages and nearly driving me nuts. Relieved to finally have it working again.

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📚 Documentation preview 📚: https://datacube-ows--1080.org.readthedocs.build/en/1080/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.64%. Comparing base (11f6787) to head (b07c766).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1080   +/-   ##
=======================================
  Coverage   93.64%   93.64%           
=======================================
  Files          43       43           
  Lines        6510     6510           
=======================================
  Hits         6096     6096           
  Misses        414      414           

Files with missing lines	Coverage Δ
datacube_ows/startup_utils.py	92.56% <100.00%> (ø)

[SpacemanPaul]

@pjonsson Any of this unnecessary? (Anything I've missed?)

[pjonsson]

My ows-rebuild patches in the apt-get upgrade -y, so it's nice to get it into the Dockerfile instead.

I have not used pydevd, but on Ubuntu, you automatically get a new PyCharm as soon as it is released. If it works the same on Windows/Mac and pydevd versions are tied to PyCharm versions, it might be easiest to just drop the version constraint on pydevd and always get the latest. But do that in a separate PR, this PR makes it work and that is worth a lot.

Unrelated to this PR, it would be nice with a datacube-ows release with the cache-fixes and your fix that makes it stop spamming the logs with warnings.

I'm out of commission now and it will most likely last for the rest of the week, so don't hold this waiting for me, but for what it is worth, I think this change looks good.