Create homebrew Ubuntu 20.04 arm64 iso

[cbrxyz]

What needs to change?

For members with an arm64 computer, it's hard to find a Ubuntu 20.04 iso file on the Internet now. Therefore, we will need to homebrew our own ARM Ubuntu 20.04 iso.

Seems like a good project for this could be: https://github.com/PJ-Singh-001/Cubic

members who are affected by shortage of an arm iso:

• @alexoj46

How would this task be tested?

1. Ensure that the iso file can be launched in a VM/emulator on an arm-based computer

[cbrxyz]

Turns out that the best solution for this issue is to just to install Ubuntu Server 20.04 and then install Ubuntu Desktop.

The steps would be:

1. Download the Ubuntu Server 20.04 arm iso, which I put on the MIL server so we don't lose it
2. Roughly follow the Getting Started docs, using either Option 3 or Option 4, and just use the server iso instead of the desktop iso.
3. Then, after finishing the installation process:

sudo apt update
sudo apt install ubuntu-desktop
sudo reboot now

... and then you should have a working arm desktop environment!

I'm going to update the docs now