feat(string): add CTStringView and CTString concepts

Redcraft.Utility/Source/Public/String/String.h

@@ -18,6 +18,9 @@ NAMESPACE_MODULE_BEGIN(Utility)
 
 NAMESPACE_PRIVATE_BEGIN
 
+template <typename T            > struct TIsTString                : FFalse { };
+template <typename T, typename A> struct TIsTString<TString<T, A>> : FTrue  { };
+
 template <typename T>
 class TCStringFromTString final : FNoncopyable
 {
@@ -58,6 +61,8 @@ private:
 
 NAMESPACE_PRIVATE_END
 
+template <typename T> concept CTString = NAMESPACE_PRIVATE::TIsTString<TRemoveCV<T>>::Value;
+
 /** The default string allocator that uses SSO and can be placed right into FAny without dynamically allocating memory. */
 template <CCharType T>
 using TDefaultStringAllocator = TInlineAllocator<(40 - 3 * sizeof(size_t)) / sizeof(T)>;