Remove numactl & Dockerfile Cleanup (#294)

- 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.

mono/latest/Dockerfile

@@ -4,7 +4,7 @@ LABEL       author="Torsten Widmann" maintainer="support@goover.de"
 
 RUN         apt update \
             && apt -y upgrade
-RUN         apt install -y fontconfig dirmngr numactl
+RUN         apt install -y fontconfig dirmngr
 RUN         apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
 RUN         sh -c 'echo "deb https://download.mono-project.com/repo/debian stable-buster main" > /etc/apt/sources.list.d/mono-official-stable.list'
 RUN         apt update