feat(ble): Adds Characteristic User Descriptor

Adds a class for 0x2901 - Characteristic User Descriptor.

This Descriptor is usual in BLE and describes with text what each characteristic is about.

Author: SuGlider

libraries/BLE/src/BLE2901.h

@@ -0,0 +1,37 @@
+/*
+   BLE2901.h
+
+     GATT Descriptor 0x2901 Characteristic User Description
+
+     The value of this description is a user-readable string
+     describing the characteristic.
+
+     The Characteristic User Description descriptor
+     provides a textual user description for a characteristic
+     value.
+     If the Writable Auxiliary bit of the Characteristics
+     Properties is set then this descriptor is written. Only one
+     User Description descriptor exists in a characteristic
+     definition.
+
+*/
+
+#ifndef COMPONENTS_CPP_UTILS_BLE2901_H_
+#define COMPONENTS_CPP_UTILS_BLE2901_H_
+#include "soc/soc_caps.h"
+#if SOC_BLE_SUPPORTED
+
+#include "sdkconfig.h"
+#if defined(CONFIG_BLUEDROID_ENABLED)
+
+#include "BLEDescriptor.h"
+
+class BLE2901 : public BLEDescriptor {
+  public:
+    BLE2901();
+    void setDescription(String desc);
+};  // BLE2901
+
+#endif /* CONFIG_BLUEDROID_ENABLED */
+#endif /* SOC_BLE_SUPPORTED */
+#endif /* COMPONENTS_CPP_UTILS_BLE2901_H_ */