Split out default CATCH_CONFIG_CONSOLE_WIDTH into its own header

This means that code that uses it no longer has to include all of
catch_config.hpp, which seems to provide significant reduction in
size of unoptimized compilation of the final static library.

src/catch2/interfaces/catch_interfaces_reporter.cpp

@@ -6,6 +6,8 @@
  */
 
 #include <catch2/interfaces/catch_interfaces_reporter.hpp>
+#include <catch2/interfaces/catch_interfaces_config.hpp>
+#include <catch2/catch_config.hpp>
 #include <catch2/internal/catch_console_colour.hpp>
 #include <catch2/catch_message.hpp>
 #include <catch2/internal/catch_list.hpp>