esp_https_ota: Add support for HTTPS based ota feature

docs/en/api-reference/system/esp_https_ota.rst

@@ -0,0 +1,35 @@
+ESP HTTPS OTA
+=============
+
+Overview
+--------
+
+``esp_https_ota`` provides simplified APIs to perform firmware upgrades over HTTPS.
+It's an abstraction layer over existing OTA APIs.
+
+Application Example
+-------------------
+
+    .. highlight:: c
+
+    ::
+
+        esp_err_t do_firmware_upgrade()
+        {
+            esp_http_client_config_t config = {
+                .url = CONFIG_FIRMWARE_UPGRADE_URL,
+                .cert_pem = (char *)server_cert_pem_start,
+            };
+            esp_err_t ret = esp_https_ota(&config);
+            if (ret == ESP_OK) {
+                esp_restart();
+            } else {
+                return ESP_FAIL;
+            }
+            return ESP_OK;
+        }
+
+API Reference
+-------------
+
+.. include:: /_build/inc/esp_https_ota.inc