feat(lib): use Checker type instead of ad-hoc logic (#318)

This makes each check into its own type that has encapsulated check
logic, meaning that it's easier to add new checker implementations in
the future.

Signed-off-by: Xe Iaso <me@xeiaso.net>

lib/checkresult.go

@@ -1,25 +0,0 @@
-package lib
-
-import (
-	"log/slog"
-
-	"github.com/TecharoHQ/anubis/lib/policy/config"
-)
-
-type CheckResult struct {
-	Name string
-	Rule config.Rule
-}
-
-func (cr CheckResult) LogValue() slog.Value {
-	return slog.GroupValue(
-		slog.String("name", cr.Name),
-		slog.String("rule", string(cr.Rule)))
-}
-
-func cr(name string, rule config.Rule) CheckResult {
-	return CheckResult{
-		Name: name,
-		Rule: rule,
-	}
-}