Centralize python setup guide

[WilliamBergamin]

Through out the docs and guides we mention how to set up a python project using pyenv, python, venv and pip, it would be nice to centralize this and reference a common resource.

The page URLs

• https://slack.dev/bolt-python/

Requirements

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[seratch]

I think having a link to a Python setup page instead is not a really great developer experience. If you can have a reusable part for many pages and embed it easily, it would be great.

[hello-ashleyintech]

@srtaalej Find virtual env creation throughout the docs (README, maintainer's guide, slack.dev) and find a way to have one standardized approach or source of truth (example areas this appears: https://github.com/slackapi/bolt-python?tab=readme-ov-file#setup and https://github.com/slackapi/bolt-python/blob/main/.github/maintainers_guide.md#python-and-friends and https://slack.dev/bolt-python/tutorial/getting-started#setting-up-your-project and https://slack.dev/bolt-python/tutorial/getting-started-http)

If possible, have some sort of variable or component that dynamically injects the same info - basically try to standardize it across the board. Could find a way to source this globally and inject it - we just want to find a way to reduce redundancy in favor of one standardized approach

Can be an exploratory PR - if one specific source isn't possible, then we can find an alternate approach. @seratch and @WilliamBergamin are good points of contact for this!