Support contributions from NixOS

[altsalt]

When using NixOS, there are a variety of changes one needs to make to get the development environment working. Some of these could be included directly in the codebase, but that may lead to other unexpected changes and/or other specialized environmental requests. Adding a relevant documentation page is a way to minimize impact, but needs to kept up-to-date and referenced appropriately.

[altsalt]

An example may be found in #89 (comment)

[altsalt]

Another note is that since my environment needs requires an override for playwright, I need to remember to avoid pushing my lockfile.