shapez used to have a nice error handler, but later it was removed. To
help debug game in both development and release cases, add a simple
error handler/screen that displays the error stack trace, lists the
installed mods and shows some build information. It also allows copying
this information to the system clipboard.
Having such an error screen should make mod development easier once the
local mod error handling is removed.
Remove some unused classes, mixins and variables, then inline ones that
have just a few usages. Also remove a few redundant properties and
replace align-items: center + justify-items: center with place-items:
center.
Can have minor effect on game appearance, most importantly the removal
of letter-spacing by default. Styles are now much lighter though.
Changes all keybinding code to use kbd instead of code as well.
