test something to ensure module evaluates when not enabled @GrahamcOfBorg test env

@ryantm That was a bit fast of a merge imo, such big changes warrant a bigger window for discussion, 1 hour is not enough

I'm not a fan of having huge number of options. See what I did in #45470 instead, which has multiple advantages (and some disadvantages) to this way. Advantages:

• Much simpler to implement, less code
• A single option doesn't clutter the docs
• Doesn't decrease evaluation time by much, evaluation time after all is linear in the number of available options
• When upstream adds/removes/changes certain config values, there's no need to update the NixOS module

Disadvantages:

• Can't type check every single value, but this can be fixed by running the config file through the package while building (needs a "check config" mode for the package though)

(This is similar to just a string based option, but that wouldn't support proper merging behavior and have no guaranteed syntax correctness.)

@infinisil sorry. I'll give more time next time.

@infinisil do you want me to rewrite the configuration stuff?

Nah I'm fine with it, it's merged already and the work is done. Unless you prefer my suggestion as well and don't mind changing it again, in which case I'll be happy to work with you towards that solution (and reverting this PR meanwhile), up to you.

In any case this way is what lots of other people are doing too (having dozens of options for every single configuration option). I just hope that this idea of only a single config option will be used more in the future.