Lots of nonfunctional clean up of tabletop stuff

[Centronias]

About the PR

Just code. Updated stuff to modern standards (assuming I know those :^) )

For reviewers, note that there are three commits:

• one for moving some files only
• one for changing from scoped namespace { ... } usage to file namespace ...; usage
• one for actual implementation changes.

I suggest looking at each commit individually rather than trying to look at them all layered together.

Why / Balance

I kinda wanna reuse the tabletop stuff for other stuff, so I wanted to clean it up.

Technical details

Lots of small things. I can enumerate them if you want.
The number of lines is because of namespace { ... } -> namespace ; changes.

Media

N/A

Requirements

• I have read and am following the Pull Request and Changelog Guidelines.
• I have added media to this PR or it does not require an ingame showcase.

Breaking changes

TabletopSetup is totally changed, but it should be easy to uptake.
I think that's the bulk of it.

Changelog

N/A