Update License Headers and normalize code style

[kantenkugel]

The current license headers are either outdated or missing completely.
While updating those, it would also be wise to discuss who should be in said license headers. Should we use one for com.almightyalpaca and another one for com.kantenkugel? Or just a combined one for both packages?

Additionally, due to me having my preferred code style placing { on same line, and IJ sometimes not remembering that I set a project-specific code style, some files have brackets placed on same line (sorry).

Considering updating the license headers will change most if not all files anyway, this would be the perfect time to also change the code style to use uniform bracket placement (I'd go with next-line bracket, like used by most of com.almightyalpaca's code already)