Implement dj::Receiver class

Again, many things were done here.

src/logid/backend/dj/Error.h

@@ -0,0 +1,30 @@
+#ifndef LOGID_HIDPP_BACKEND_DJ_ERROR_H
+#define LOGID_HIDPP_BACKEND_DJ_ERROR_H
+
+#include <cstdint>
+#include <stdexcept>
+
+namespace logid {
+namespace backend {
+namespace dj
+{
+    class Error : public std::exception
+    {
+    public:
+        enum ErrorCode : uint8_t
+        {
+            Unknown = 0x00,
+            KeepAliveTimeout = 0x01
+        };
+
+        Error(uint8_t code);
+
+        virtual const char* what() const noexcept;
+        uint8_t code() const noexcept;
+
+    private:
+        uint8_t _code;
+    };
+}}}
+
+#endif //LOGID_HIDPP_BACKEND_DJ_ERROR_H