* new: SensorManager

* BasChatMesh: new onContactRequest(), for PAYLOAD_TYPE_REQ handling.
* companion, repeater and room_server: now with basic 'plumbing' to handle REQ_TYPE_GET_TELEMETRY_DATA (0x03).
* dependency: added CayenneLPP to libdeps
* all target.* modules now with a stub 'sensors' object.

examples/simple_secure_chat/main.cpp

@@ -254,6 +254,10 @@ protected:
     Serial.printf("   %s\n", text);
   }
 
+  uint8_t onContactRequest(const ContactInfo& contact, uint32_t sender_timestamp, const uint8_t* data, uint8_t len, uint8_t* reply) override {
+    return 0;  // unknown
+  }
+
   void onContactResponse(const ContactInfo& contact, const uint8_t* data, uint8_t len) override {
     // not supported
   }