chore: update gitignore list (#9437)

Updated the gitignore list with the command : `go run scripts/generate-gitignores.go`

options/gitignore/Magento2

@@ -0,0 +1,54 @@
+/sitemap
+/sitemap.xml
+/pub/sitemap
+/pub/sitemap.xml
+/app/config_sandbox
+/app/etc/config.php
+/app/etc/env.php
+/app/code/Magento/TestModule*
+/lib/internal/flex/uploader/.actionScriptProperties
+/lib/internal/flex/uploader/.flexProperties
+/lib/internal/flex/uploader/.project
+/lib/internal/flex/uploader/.settings
+/lib/internal/flex/varien/.actionScriptProperties
+/lib/internal/flex/varien/.flexLibProperties
+/lib/internal/flex/varien/.project
+/lib/internal/flex/varien/.settings
+/.grunt
+/.php_cs.cache
+/grunt-config.json
+/dev/tools/grunt/configs/local-themes.js
+ 
+/pub/media/*.*
+!/pub/media/.htaccess
+/pub/media/attribute/*
+!/pub/media/attribute/.htaccess
+/pub/media/analytics/*
+/pub/media/catalog/*
+!/pub/media/catalog/.htaccess
+/pub/media/customer/*
+!/pub/media/customer/.htaccess
+/pub/media/downloadable/*
+!/pub/media/downloadable/.htaccess
+/pub/media/favicon/*
+/pub/media/import/*
+!/pub/media/import/.htaccess
+/pub/media/logo/*
+/pub/media/theme/*
+/pub/media/theme_customization/*
+!/pub/media/theme_customization/.htaccess
+/pub/media/wysiwyg/*
+!/pub/media/wysiwyg/.htaccess
+/pub/media/tmp/*
+!/pub/media/tmp/.htaccess
+/pub/media/captcha/*
+!/pub/media/captcha/.htaccess
+/pub/static/*
+!/pub/static/.htaccess
+ 
+/var/*
+!/var/.htaccess
+/vendor/*
+!/vendor/.htaccess
+/generated/*
+!/generated/.htaccess