Documentation improvements

• The chart in here says OAS in the deploy part https://docs.stackspin.net/en/latest/for_developers/design.html
• flux2/infrastructure doesn't exist as a folder https://docs.stackspin.net/en/v1.0/installation/install_stackspin.html#:~:text=flux2/infrastructure
• be run in the machine: https://docs.stackspin.net/en/latest/installation/install_cli.html#:~:text=be%20run%20the%20provisioning%20machine
• Clarify requirements of the provisioning machine