Improve documentation for installing docker on Windows Home

[sebbacon]

This is what the official docs have to say:

• Hyper-V and Containers Windows features must be enabled.
• The following hardware prerequisites are required to successfully run Client Hyper-V on Windows 10:
  • 64 bit processor with Second Level Address Translation (SLAT)
  • 4GB system RAM
  • BIOS-level hardware virtualization support must be enabled in the BIOS settings. For more information, see Virtualization.

Our test user has a "very late" build of Windows 10 Home: they went through the requirements trying to find out if they had SLAT. They added:

I couldn’t get the virtualization stuff to work either.

There were a series of more & more complex things for a simpleton like me to do with Hyper-V and Containers Windows. I also enabled WSL1 but didn’t get WSL2 to go.

I don’t know if I was close to getting it going, but each time I got something, I found there was another 2 levels to negotiate.

[remlapmot]

You probably know - in my opinion it's much better if the user installs WSL 2 if they can as Docker Desktop will use the WSL 2 engine (I want to say kernel) , in the Docker Desktop settings check the "Use WSL 2 based engine" box.

WSL 2 system calls run much faster than WSL 1.

[sebbacon]

Whoops I opened this in the wrong repo. Copied opensafely/documentation#191