examples: add logrotate configuration

examples/chrony.logrotate

@@ -0,0 +1,8 @@
+/var/log/chrony/*.log {
+    missingok
+    nocreate
+    sharedscripts
+    postrotate
+        /usr/bin/chronyc -a cyclelogs > /dev/null 2>&1 || true
+    endscript
+}