Don't automatically restore saved DNS settings when switching networks

smol tweaks to nameserver test queries

fix restoreDNS errors

add some debugging information

fix wront type in log msg

set send logs command timeout to 5 mins

when the runningIface is no longer up, attempt to find a new interface

prefer default route, ignore non physical interfaces

prefer default route, ignore non physical interfaces

add max context timeout on performLeakingQuery with more debug logs

cmd/cli/os_linux.go

@@ -195,6 +195,12 @@ func resetDNS(iface *net.Interface) (err error) {
 	})
 }
 
+// restoreDNS restores the DNS settings of the given interface.
+// this should only be executed upon turning off the ctrld service.
+func restoreDNS(iface *net.Interface) (err error) {
+	return err
+}
+
 func currentDNS(iface *net.Interface) []string {
 	for _, fn := range []getDNS{getDNSByResolvectl, getDNSBySystemdResolved, getDNSByNmcli, resolvconffile.NameServers} {
 		if ns := fn(iface.Name); len(ns) > 0 {