Repository refactor, folder structure & more about wceu2023

[vagelisp]

I will merge the #6 PR to go with this, as we all agreed yesterday that it's OK.
I added the old output.css file as a failsafe; we can remove that in the following days.

[vagelisp]

The old file's path has been changed, so I adjusted the path on the website. Everything seems to be working fine.
I'll do some more testing and import the new file.

I am just documenting the steps/actions here in case anyone wants to follow/comment/change something.

Thanks.

[vagelisp]

I removed some of the CSS we had on "Additional CSS."
Some of the rules are causing conflicts (i.e. with the menu as there's a global ul style rule ), and some were duplicates since Ioana added typography on git. I also extended the heading rules a bit to make them global ( ofc we can override when needed ).

Also, I switched from the output.css to the new CSS file so I am moving this into the backup folder.