This commit add support for ctrld to run on freebsd, supported platforms
are amd64/arm64/armv6/armv7,386.
Supporting freebsd also requires adding debian and openresolv resolvconf.
Updates #47
For interface managed by systemd-networkd, systemd-resolved can not
reset DNS. To fix this, attempting to check before the run loop and set
the suitable manager for the system.
Updates #55
If ctrld setup the interface correctly, the interface DNS is set to
ctrld listener address. At boot time, the ctrld is not up yet, so it
would break the processing Control D config fetching.
Fixing this by waiting for network up before doing the query.
This commit adds config params to enable local DNS response caching and
control its behavior, allow tweaking the cache size, ttl override and
serving stale response.
