move arpnip and arpwalk to worker plugins

lib/App/Netdisco/Worker/Plugin/Arpnip.pm

@@ -0,0 +1,31 @@
+package App::Netdisco::Worker::Plugin::Arpnip;
+
+use Dancer ':syntax';
+use App::Netdisco::Worker::Plugin;
+use aliased 'App::Netdisco::Worker::Status';
+
+use App::Netdisco::Util::Device 'is_arpnipable_now';
+use App::Netdisco::Transport::SNMP ();
+
+register_worker({ primary => true }, sub {
+  my ($job, $workerconf) = @_;
+  my $device = $job->device;
+
+  return Status->error('arpnip failed: unable to interpret device param')
+    unless defined $device;
+
+  my $host = $device->ip;
+
+  return Status->done("arpnip skipped: $host not yet discovered")
+    unless $device->in_storage;
+
+  return Status->defer("arpnip skipped: $host is pseudo-device")
+    if $device->vendor and $device->vendor eq 'netdisco';
+
+  return Status->defer("arpnip deferred: $host is not arpnipable")
+    unless is_arpnipable_now($device);
+
+  return Status->done('Arpnip is able to run.');
+});
+
+true;