file-sys: Default heavy-weight class destructors in the cpp file

Several classes have a lot of non-trivial members within them, or don't
but likely should have the destructor defaulted in the cpp file for
future-proofing/being more friendly to forward declarations.

Leaving the destructor unspecified allows the compiler to inline the
destruction code all over the place, which is generally undesirable from
a code bloat perspective.

src/core/file_sys/control_metadata.cpp

@@ -20,6 +20,8 @@ NACP::NACP(VirtualFile file) : raw(std::make_unique<RawNACP>()) {
     file->ReadObject(raw.get());
 }
 
+NACP::~NACP() = default;
+
 const LanguageEntry& NACP::GetLanguageEntry(Language language) const {
     if (language != Language::Default) {
         return raw->language_entries.at(static_cast<u8>(language));