Building a local LXD-based Lab

I often have the need to spin up a Linux host to perform some quick testing for something, and the amount of legwork and time to get a simple VM up and running is often as time-consuming as getting the software installed to interact with it. I needed something that was quicker to get me bootstrapped, simple enough to not require me to learn a whole ton to get going, and repeatable enough for me to even write some dirty scripts to make standing something up repeatable.