Modernize ApplicationConfiguration

Add types to properties

Add property $name explicitly

This fixes the following issue:
PHP Deprecated:
Creation of dynamic property ApplicationConfiguration::$name is deprecated
in /var/51-wwwroot/obsidian/workspaces/src/Engines/Apps/ApplicationConfiguration.php on line 66

Following style conventions for class end

Differential Revision: https://devcentral.nasqueron.org/D3827