- Removed the `numactl` package from all images as SteamCMD no longer seems to have issues logging in with a real Steam account (at least on bookworm, which all these images use).
The following cleanup changes only apply to Dockerfiles that had `numactl` removed:
- Changed all Dockerfiles to use `apt` (instead of `apt-get`) for consistency.
- Changed all `apt install` packages to a "list" format for consistency and easier diff reading for future package additions/removals.
- Added `locales` to `games\source\Dockerfile` and set the locale.
- Moved all instances of the `useradd` command down with the other user and working directory commands. Also added the shell specification flag if it was missing.
- Unified all Dockerfiles to use space-indenting and fixed some indent spacing.
- Cleaned up some comments.
