feat: add debian12 scripts

- nftables_is_enabled.sh 		-> 4.2.9
- nftables_has_table.sh 		-> 4.2.4
- nftables_has_base_chains.sh 		-> 4.2.5
- nftables_rules_permanent.sh		-> 4.2.10
- nftables_default_deniy_policy.sh	-> 4.2.8

tests/hardening/nftables_default_deny_policy.sh

@@ -0,0 +1,16 @@
+# shellcheck shell=bash
+# run-shellcheck
+test_audit() {
+    describe Prepare test
+    apt install -y nftables
+
+    # running on a non privilieged container, wont test much...
+    describe Running on blank host
+    register_test retvalshouldbe 1
+    # shellcheck disable=2154
+    run blank "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    describe clean test
+    apt remove -y nftables
+
+}