Added missing operators in MeshBoundaryTagsLayer

public:

   using GlobalIndexType   = typename EntityTraitsType::GlobalIndexType;

   MeshBoundaryTagsLayer() = default;

   explicit MeshBoundaryTagsLayer( const MeshBoundaryTagsLayer& other ) {}

   template< typename Device_ >

   MeshBoundaryTagsLayer( const MeshBoundaryTagsLayer< MeshConfig, Device_, DimensionTag >& other ) {}

   MeshBoundaryTagsLayer& operator=( const MeshBoundaryTagsLayer& other ) { return *this; }

   template< typename Device_ >

   MeshBoundaryTagsLayer& operator=( const MeshBoundaryTagsLayer< MeshConfig, Device_, DimensionTag >& other ) { return *this; }

   bool setNumberOfEntities( const GlobalIndexType& entitiesCount )

   {

      return true;