luci-app-adblock: sync with adblock 3.8.0
* add support for the 'null' blocking variant in dnsmasq
(via addn-hosts), see new select box 'DNS Variant'
* add support for 'DNS File Reset', where the final DNS blockfile
will be purged after DNS backend loading (save storage space)
* Provide additional Runtime information:
'DNS Variant' and 'Backup Directory'
* add E-Mail notification options to LuCI
Signed-off-by: Dirk Brenken <dev@brenken.org>
(cherry picked from commit
9400fc7536399d38fb81a43a49911f0248a15e7b)