add pre post backup scripts

backup_scripts/gitea/post_backup.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+HOST_GITEA_BACKUP_DIR="/backup/gitea"
+HOST_CONFIG_BACKUP_DIR="/backup/system_dirs"
+
+rm -rf ${HOST_GITEA_BACKUP_DIR}/*
+rm -rf ${HOST_CONFIG_BACKUP_DIR}/*
+# notification
+