Option to make modules opt-in about stylix

[danth]

I'd like to keep a way to turn on relevant modules automatically - most users won't check the commits in every update to know when there are new modules to enable. A way to disable certain modules would be useful though, and as you mentioned there are some things which should only be enabled when the user chooses. We can add a list of modules in the README to make users aware of those which always need to be opted into.

I'd suggest creating an option like stylix.targets.whatever.enable for each module. The Lightline module would default to false, and for other modules, the default can be an expression like programs.whatever.enable && stylix.autoEnable. Users would be able to set autoEnable = false to make everything opt-in, while others can leave it on the default true to keep the current behaviour. Or perhaps false should be the default, however that would break any existing usage.

[FlorianFranzen]

I would still appreciate if the module could be loaded without it being activated for example unless I do something like stylix.enable = true. Right now just including the stylix module will cause the missing stylix.image option to through an error.

[danth]

What happens if you set stylix.autoEnable = false?