Update readme with latest versions and missed steps

The current readme version has a few small but criticall errors that can cause new developers to get stuck in their first setup.

[x] It could be good to clarify for new junior developers that you start by cloning the github repo into a new folder. As its written now it can be easy to confuse the make firstrun with somthing beeing related to installing a docker container
[x] Python 3.11 install instructions seems outdated
[x] The docker-compose-plugin should no longer be needed and can be removed
[x] Add missing depndency to install python virtual environment and explain where to put the folder
[ ] Is the Make init command really neccesary to have in the readme since its seems to run in make firstsetup?
[ ] List third party dependencies like Stripe, Accessy, Mailgun and the SMS-service (name???) and explain which are optional

makerspace / makeradmin