refactor(treewide): get rid of compile time build environment introspection

It's cursed and not very useful. Still a few uses of ctor left, but oh well.

src/service/Cargo.toml

@@ -118,7 +118,6 @@ webpage.optional = true
 blurhash.workspace = true
 blurhash.optional = true
 recaptcha-verify = { version = "0.1.5", default-features = false }
-ctor.workspace = true
 
 [target.'cfg(all(unix, target_os = "linux"))'.dependencies]
 sd-notify.workspace = true