Use known versions of pip and setuptools

[thclark]

In our production containers for the services, we do something like:

FROM windpioneers/gdal-python:statutory-crow-gdal-2.4.1-python-3.8-slim as base

# Upgrade to latest pip and setuptools
RUN pip install --upgrade pip setuptools

But we shouldn't need to do this, and it sometimes causes problems because over subsequent releases the version of pip used can vary (it's not pinned). We expect updates to pip if we actually change the dev stack, but not from release to release of the end services (same story with poetry).

So, we should RUN pip install --upgrade pip setuptools when building the stack, which will allow us to remove that update command in order to stabilise production builds. If we need to update pip at some point, that should be done here at the stack level, not by the individual services.

[thclark]

Deprecating since #24 as the move to uv replaces pip and setuptools.