Support adjust volume with knob in SenseCAP Watcher (#399)

* fix typo, add missing prefix `CONFIG` to `ESP_TASK_WDT_TIMEOUT_S`

* add KNOB gpio spec to sensecap config

* create new knob component

* implement ajust output volume with knob

* modify function name to UpperCamelCase

* Tidy up comments and logs

main/boards/common/knob.h

@@ -0,0 +1,25 @@
+#ifndef KNOB_H_
+#define KNOB_H_
+
+#include <driver/gpio.h>
+#include <functional>
+#include <esp_log.h>
+#include <iot_knob.h>
+
+class Knob {
+public:
+    Knob(gpio_num_t pin_a, gpio_num_t pin_b);
+    ~Knob();
+
+    void OnRotate(std::function<void(bool)> callback);
+
+private:
+    static void knob_callback(void* arg, void* data);
+
+    knob_handle_t knob_handle_;
+    gpio_num_t pin_a_;
+    gpio_num_t pin_b_;
+    std::function<void(bool)> on_rotate_;
+};
+
+#endif // KNOB_H_