exit: move final and early code to internal package

Exit cleanup state information is now stored in a dedicated struct and built up using methods of that struct.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

internal/early.go

@@ -0,0 +1,16 @@
+package internal
+
+import (
+	"fmt"
+
+	"git.ophivana.moe/cat/fortify/internal/util"
+)
+
+var SdBootedV = func() bool {
+	if v, err := util.SdBooted(); err != nil {
+		fmt.Println("warn: read systemd marker:", err)
+		return false
+	} else {
+		return v
+	}
+}()