[#137] Refactor context data retrievers

Signed-off-by: Roman Loginov <r.loginov@yadro.com>

api/handler/util.go

@@ -131,7 +131,7 @@ func parseRange(s string) (*layer.RangeParams, error) {
 }
 
 func getSessionTokenSetEACL(ctx context.Context) (*session.Container, error) {
-	boxData, err := layer.GetBoxData(ctx)
+	boxData, err := middleware.GetBoxData(ctx)
 	if err != nil {
 		return nil, err
 	}