Libraries: Use default constructors/destructors in LibGemini

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules

"The compiler is more likely to get the default semantics right and
you cannot implement these functions better than the compiler."

Userland/Libraries/LibGemini/GeminiRequest.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2020-2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -10,14 +10,6 @@
 
 namespace Gemini {
 
-GeminiRequest::GeminiRequest()
-{
-}
-
-GeminiRequest::~GeminiRequest()
-{
-}
-
 ByteBuffer GeminiRequest::to_raw_request() const
 {
     StringBuilder builder;