Cleaning up the build process

[mquinnfd]

Prerequisites

• [X] I am using the latest version of Locust
• [X] I am suggesting a new feature, not asking a question

Description

Overview

After v1 of the migration to the poetry build system was completed, some kruft was left over and can now be tackled individually, and with care.

I'm using this issue to catalogue the things that should ideally be cleaned up and to contain discussion as well.

• Slim down the built docker image
• Introduce poe to run pre-build hooks and remove janky pre-build hook
• Switch out the poetry installation in the pipeline to https://github.com/snok/install-poetry
• Resurrect the MacOS build
• Clean up use (or not use) of poetry x commands in the GH Actions pipeline
• Ensure caching of venv steps in build are doing what they're supposed to do
• Reduce GH Actions building of the project to the bare minimum