Rewording around config as a must have #126

We had the community call https://www.youtube.com/watch?reload=9&v=2D7Wjoj2lXc and it was clear the optional need for a config attribute or <py-config> or even <mpy-config> is not super clear in our docs.

We start the configuration section like this: https://docs.pyscript.net/2024.6.1/user-guide/configuration/

We need to tell PyScript how we want such Python environments to be configured

While true as a statement, this is a bit misleading in there to me: we don't need to tell anything to any interpreter ... unless we do.

This issue is to try brainstorming or improve that initial Configuration paragraph that sounds like a config is needed by all mean, and we already had users slightly confused about empty configs and the config meaning in general.