backend:
* add new 'manual mode' to re-use blocklist backups during startup,
get fresh lists only via manual reload or restart action
* additional free memory check during dns restart to prevent OOM errors
* removed palevo tracker from default config,
this tracker has been discontinued
* cosmetics
LuCI frontend (see luci repo):
* add new 'manual mode' under extra options
Signed-off-by: Dirk Brenken <dev@brenken.org>