Filters are now saved to a file
Also, they're loaded from the file on startup
Filter ID is not passed to the CoreDNS plugin config (server-side AG DNS must be changed accordingly)
Some minor refactoring, unused functions removed
* commit '880ad362a849cc53729128b614a4d4cc1d696750':
Makefile -- use variable for target binary
coredns plugin -- remove debug logging
single binary -- coredns also tries to parse arguments, it kills itself on unknown flags
Update makefile to build only one binary instead of two
WIP -- single binary -- works, replies to DNS, but need to check what got broken
