Bugfix/fix windows warnings (#5121)

* fix windows warnings
* don't use <date/datetime.h> in global scope so it doesn't interfere with iresearch

lib/Basics/datetime.cpp

@@ -20,6 +20,8 @@
 /// @author Manuel Baesler
 ////////////////////////////////////////////////////////////////////////////////
 
+#include <date/date.h>
+#include <regex>
 #include "Basics/datetime.h"
 #include "Logger/Logger.h"
 #include "lib/Basics/StringUtils.h"

lib/Basics/datetime.h

@@ -24,7 +24,7 @@
 #define ARANGODB_BASICS_DATETIME_H 1
 
 #include <boost/algorithm/string.hpp>
-#include <date/date.h>
+#include <chrono>
 
 #include <regex>
 

tests/Basics/datetime.cpp

@@ -1,6 +1,7 @@
 
 #include "Basics/datetime.h"
 #include "catch.hpp"
+#include <date/date.h>
 
 using namespace arangodb;
 using namespace arangodb::basics;