[Breaking] Update callbacks to use NimBLEConnInfo.

Change the callback functions that receive a ble_gap_conn_desc pointer to instead receive a NimBLEConnInfo reference.

* Add a reason parameter to the server disconnect callback.

* Remove connect and disconnect callback that do not receive info parameters.

* Remove onRead and onWrite Characteristic callbacks that do not receive info parameters.

* Add info parameter to Descriptor onWrite and onRead callbacks.

* Add details to migration guide.

src/NimBLEConnInfo.h

@@ -9,6 +9,9 @@
 class NimBLEConnInfo {
 friend class NimBLEServer;
 friend class NimBLEClient;
+friend class NimBLECharacteristic;
+friend class NimBLEDescriptor;
+
     ble_gap_conn_desc m_desc;
     NimBLEConnInfo()                       { m_desc = {}; }
     NimBLEConnInfo(ble_gap_conn_desc desc) { m_desc = desc; }