[cleanup] Remove deprecated type_traits conjunction, disjunction, negation

CHANGELOG.md

@@ -61,6 +61,8 @@ In order to build the DUNE core modules you need at least the following software
   instead.
 - The deprecated header `dune/common/to_unique_ptr.hh` has been removed. Use
   `std::unique_ptr` or `std::shared_ptr` instead.
+- Deprecated `conjunction`, `disjunction`, and `negation` have been removed. Instead,
+  use the structs from `<type_traits>` introduced with C++17.
 
 
 # Release 2.9

dune/common/std/type_traits.hh

@@ -233,55 +233,6 @@ namespace Std
 
 #endif // DUNE_HAVE_CXX_EXPERIMENTAL_IS_DETECTED
 
-
-
-  // conjunction
-  // -----------
-
-  /**
-   * \brief forms the logical conjunction of the type traits B...
-   *
-   * \note This functionality is part of the C++17 standard.
-   *
-   * \ingroup CxxUtilities
-   **/
-  template< class... B >
-  struct [[deprecated("Will be removed after release 2.8. Use std::conjunction instead.")]] conjunction
-    : std::conjunction<B...>
-  {};
-
-
-  // disjunction
-  // -----------
-
-  /**
-   * \brief forms the logical disjunction of the type traits B...
-   *
-   * \note This functionality is part of the C++17 standard.
-   *
-   * \ingroup CxxUtilities
-   **/
-  template< class... B >
-  struct [[deprecated("Will be removed after release 2.8. Use std::disjunction instead.")]] disjunction
-    : std::disjunction<B...>
-  {};
-
-
-  // negation
-  // --------
-
-  /**
-   * \brief forms the logical negation of the type traits B...
-   *
-   * \note This functionality is part of the C++17 standard.
-   *
-   * \ingroup CxxUtilities
-   **/
-  template<class B>
-  struct [[deprecated("Will be removed after release 2.8. Use std::negation instead.")]] negation
-    : std::negation<B>
-  {};
-
 } // namespace Std