Switch to std::filesystem

Drop the dependency on Boost.Filesystem

Change-Id: I5d6f6fe38cd0cf1c6996221188fa63db146dc9f9
diff --git a/wscript b/wscript
index 1e18344..e0fd3af 100644
--- a/wscript
+++ b/wscript
@@ -119,7 +119,7 @@
                    'For more information, see https://redmine.named-data.net/projects/nfd/wiki/Boost')
 
     # Boost.Log requires Boost.Thread
-    boost_libs = ['chrono', 'filesystem', 'log', 'thread']
+    boost_libs = ['chrono', 'log', 'thread']
 
     # Boost.Date_Time is header-only since 1.73
     if conf.env.BOOST_VERSION_NUMBER < 107300: