Add support for time entities (#6399)

* Add time entities

* Add tests

* Add myself to datetime codeowners

* Fix publishing times with 0 values

* Log performing TimeCall

* Implement `on_time` trigger

* Rename var

* Fix initial value for time

* Add arg name for clarity

* Remove useless checks

esphome/components/web_server/web_server.h

@@ -8,9 +8,9 @@
 
 #include <vector>
 #ifdef USE_ESP32
-#include <deque>
 #include <freertos/FreeRTOS.h>
 #include <freertos/semphr.h>
+#include <deque>
 #endif
 
 #if USE_WEBSERVER_VERSION >= 2
@@ -230,6 +230,15 @@ class WebServer : public Controller, public Component, public AsyncWebHandler {
   std::string date_json(datetime::DateEntity *obj, JsonDetail start_config);
 #endif
 
+#ifdef USE_DATETIME_TIME
+  void on_time_update(datetime::TimeEntity *obj) override;
+  /// Handle a time request under '/time/<id>'.
+  void handle_time_request(AsyncWebServerRequest *request, const UrlMatch &match);
+
+  /// Dump the time state with its value as a JSON string.
+  std::string time_json(datetime::TimeEntity *obj, JsonDetail start_config);
+#endif
+
 #ifdef USE_TEXT
   void on_text_update(text::Text *obj, const std::string &state) override;
   /// Handle a text input request under '/text/<id>'.