Add a switch to disable/enable all NextDNS filtering

[hjk789]

When disabled, this switch would memorize all blocklists and TLDs set to be blocked and would remove all of them from the profile. When enabled, NXE would take the memorized blocklists and TLDs and add them back. This process would be nearly instantaneous.

Caveat: This wouldn't consider the denylist, as the entries need to be added/removed one by one. So at most NXE could enable/disable the denylist entries if there are less than 5 entries in the profile.