Make logs persistent over reboot and cleanup (#61)

* Create hassos-persists-journald

* Create hassos-persists-journald.service

* Set ln & permission

* Enable persists journald

* Update hassos-persists-journald

buildroot-external/rootfs-overlay/usr/sbin/hassos-persists-journald

@@ -0,0 +1,29 @@
+#!/bin/sh
+set -e
+
+MACHINE_ID=$(cat /etc/machine-id)
+CURRENT_LOGS=/var/log/journal/${MACHINE_ID}
+
+# Cleanup
+if [ ! -d ${CURRENT_LOGS} ];
+    rm -rf /var/log/journal/*
+    exit 0
+fi
+
+# Loop all logs folder and move
+for log_folder in /var/log/journal/*; do
+    # Not a log folder
+    if [ ! -d ${log_folder} ]; then
+        continue
+    fi
+    
+    # Current log folder
+    if (echo ${log_folder} | grep ${MACHINE_ID}); then
+        continue
+    fi
+    
+    mv ${log_folder}/* ${CURRENT_LOGS}/
+    rm -rf ${log_folder}
+done
+
+journalctl --vacuum-size=20M