refactor light fixture placing

[zjdtmkhzt]

About the PR

Refactors light fixture placement code a bit to move the stuff out of the walls and floors and into the light fixture object.

Why's this needed?

• The initial impetus for this was to make it possible to simply place light fixtures onto windows.
• Light fixtures should now also be offset correctly depending on the wall sprite, like those that are defined in maps already are.
• Removes a lot of sort of duplicate code?
• Ideally it will also prevent the thing where you smack walls with the fixtures while placing them.

Changelog

(u) zjdtmkhzt
(+) Light fixtures can now be placed directly on windows.

[zjdtmkhzt]

I still have some minor merge conflicts to resolve and want to test it a bit before then, after that it should be good to merge hopefully.

Also, the RCD will still smack things with this, but I'd rather change that in a subsequent PR since this is already sizable and I might have to shuffle some RCD code around.

[ZeWaka]

finally, nice

[zjdtmkhzt]

Also added functionality now for stacking several lights on one tile, if it makes sense with the types and directions.

[flappybatpal]

Tested ingame and seems good.