Remove support for EOL Apache 2.0 and 2.2 in favor of 2.4+ (#14664)

Apache 2.2 has been marked as EOL in December 2017 and doesn't receive
security patches any longer. Also, most *nix distributions and packages
mostly support 2.4 as minimum by now.

On Windows, this removes the configure option --enable-apache2-2handler
and merges the --enable-apache2handler and --enable-apache2-4handler
into a single option with favoring the --enable-apache2handler.

- The upstream MODULE_MAGIC_NUMBER is deprecated in favor of
  MODULE_MAGIC_NUMBER_MAJOR in apache2/ap_mmn.h
- The initial upstream MODULE_MAGIC_NUMBER_MAJOR was 20111025 in Apache
  2.4.0
- The upstream APLOG_USE_MODULE is always available since Apache 2.3.6
- The upstream CORE_PRIVATE is unnecessary and ignored since Apache
  2.4.0

See:
https://forum.apachehaus.com/news-general-discussion/apache-2-2-users-your-time-is-running-out/

Discussion: https://news-web.php.net/php.internals/124067

sapi/apache2handler/sapi_apache2.c

@@ -388,7 +388,7 @@ static int php_apache2_startup(sapi_module_struct *sapi_module)
 
 static sapi_module_struct apache2_sapi_module = {
 	"apache2handler",
-	"Apache 2.0 Handler",
+	"Apache 2 Handler",
 
 	php_apache2_startup,				/* startup */
 	php_module_shutdown_wrapper,			/* shutdown */