* Added fork sync workflow(syncs the main branch with upstream every 30 minutes)
* Added monthly workflow run deletion(all skipped or canceld and runs older than 30days will be deleted)
* Removed Docker image build for main branch on forks
* Added documentation how to enable sync and docker build workflows
Unify the hosts file parsing between the hosts resolver and lists so
the resolver supports more data sources than local files.
Lists' group cache is now re-used if refresh fails.
Also improve lookups in hosts:
Instead of iterating through all hosts+aliases for each A/AAAA query,
we can do a single lookup.
For PTR we search through only the hosts with an IP version that matches
the question. And compare IPs instead of building the reverse DNS name
for each IP in the hosts database.
Kwitsch