Add host target platform (#4783)

Co-authored-by: Otto winter <otto@otto-winter.com>

esphome/components/mdns/mdns_host.cpp

@@ -0,0 +1,18 @@
+#ifdef USE_HOST
+
+#include "esphome/components/network/ip_address.h"
+#include "esphome/components/network/util.h"
+#include "esphome/core/log.h"
+#include "mdns_component.h"
+
+namespace esphome {
+namespace mdns {
+
+void MDNSComponent::setup() { this->compile_records_(); }
+
+void MDNSComponent::on_shutdown() {}
+
+}  // namespace mdns
+}  // namespace esphome
+
+#endif