pfBlockerNG: EasyList and Python mode improvements

* Remove support for Python 2
* Fix TypeError on DHCP staticmap check (General)
* Fix detection of EasyLists by pre-scanning the file (General)
* Fix empty response when blocking alternating A and AAAA records (Python)
* Support parsing and applying EasyList exclusions (Python)
* Support parsing and applying EasyList regular expressions (Python)
* Temporary workaround for cache hit invalidation (Python)
* Add debug mode (Python)
* Add tracing mode (Python) (manual, no GUI, not development only)
* Improve logging and error handling (Python)
* Make I/O operations asynchronous (Python)

Author: andrebrait