Added PHP 7 support to .htaccess files and removed support for PHP 5

PHP 5 sections have been removed from all .htaccess files. The root .htaccess file now has a section for PHP 7 settings. This brings .htaccess files into alignment with Drupal's PHP requirements.

If you have a custom .htaccess file and its PHP settings are working, you can keep using your existing .htaccess file unchanged. If you are upgrading from PHP 5 to PHP 7, you should copy the custom settings that you need from the PHP 5 section to the PHP 7 section.