[libcxx][modularisation] moves <utility> content out of <type_traits>

Moves:

* `std::move`, `std::forward`, `std::declval`, and `std::swap` into
  `__utility/${FUNCTION_NAME}`.
* `std::swap_ranges` and `std::iter_swap` into
  `__algorithm/${FUNCTION_NAME}`

Differential Revision: https://reviews.llvm.org/D103734

NOKEYCHECK=True
GitOrigin-RevId: 6adbc83ee9e46b476e0f75d5671c3a21f675a936
diff --git a/include/vector b/include/vector
index 95ef439..bf193e5 100644
--- a/include/vector
+++ b/include/vector
@@ -276,6 +276,7 @@
 #include <__debug>
 #include <__functional_base>
 #include <__split_buffer>
+#include <__utility/forward.h>
 #include <algorithm>
 #include <climits>
 #include <compare>