feat: make an MVP website for quickemu and family

[flexiondotorg]

I confirm this feature has not been previously requested

• I have searched the issues and this feature has not previously been requested

Describe the solution you'd like

Add landing pages for Quickemu, Quickgui and Quicktest that briefly describe what each project is with a feature run down, screenshots/animations and jumping-off points to the various useful places to learn more.

Additional context
Let's use this issue to discuss what to create. I (@flexiondotorg) don't want to be too prescriptive because I value the input of an actual web developer 😃

[lj3954]

I hate having to make mostly unrelated comments to a discussion like this, but I wanted to make sure it's clear the reason I added this to the tasks. This issue replaces #744 (which GitHub automatically moved to "completed" upon the closure of the issue), so I've added it to what I believe to be the appropriate position.