Add support for button entities (#2824)

esphome/components/button/automation.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "esphome/components/button/button.h"
+#include "esphome/core/automation.h"
+#include "esphome/core/component.h"
+
+namespace esphome {
+namespace button {
+
+template<typename... Ts> class PressAction : public Action<Ts...> {
+ public:
+  explicit PressAction(Button *button) : button_(button) {}
+
+  void play(Ts... x) override { this->button_->press(); }
+
+ protected:
+  Button *button_;
+};
+
+class ButtonPressTrigger : public Trigger<> {
+ public:
+  ButtonPressTrigger(Button *button) {
+    button->add_on_press_callback([this]() { this->trigger(); });
+  }
+};
+
+}  // namespace button
+}  // namespace esphome