* Import attrs of profiles automatically with `defaultImport`.
* Refactor profiles to ensure all are functions returning a module.
* Add a suites.nix with collections of profiles.
* Add suites as `specialArgs` to modules.
* Add suite import to NixOS host.
Resolves#6 by breaking out the disabling of mitigations into it's own module.
Now users must explicitly accept the risk of disabling Spectre and Meltdown
mitigations with `security.mitigations.acceptRisk` in addition to actually
disabling them with `security.mitigations.disable`.
