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/CMakeLists.txt

@@ -36,6 +36,7 @@ set(INTERNAL_HEADERS
     ${SOURCES_DIR}/generators/catch_generators_all.hpp
     ${SOURCES_DIR}/interfaces/catch_interfaces_all.hpp
     ${SOURCES_DIR}/matchers/internal/catch_matchers_impl.hpp
+    ${SOURCES_DIR}/internal/catch_console_width.hpp
     ${SOURCES_DIR}/internal/catch_container_nonmembers.hpp
     ${SOURCES_DIR}/catch_approx.hpp
     ${SOURCES_DIR}/internal/catch_assertion_handler.hpp