Add Automatic Installation of Support for i386

[bliutech]

Some CTF challenges for binary analysis & binary exploitation are built with 32-bit x86 (i.e. i386). While CTF Dev Container is x86-64 and is compatible with 32-bit binaries, it requires some additional information shown below which may not be the most intuitive or easy to debug for beginners. Add the installation shown below would be helpful to make this process easier. From experimentation, I believe just the following commands are necessary.

sudo dpkg --add-architecture i386
sudo echo "foreign-architecture i386" > /etc/dpkg/dpkg.cfg.d/multiarch

https://askubuntu.com/questions/454253/how-to-run-32-bit-app-in-ubuntu-64-bit