php 8.2/8.3 deprecation notices

[msanderson]

With the current construct of default_config.php, deprecation notices like "Creation of dynamic property Configs::*** is deprecated in ..../default_config.php on line NN;" are generated. These are visible in apache error logs in CS' configuration. A redacted line

[Tue Mar 25 09:25:53.599455 2025] [proxy_fcgi:error] [pid 567944:tid 127231909168832] [client 206.87.248.83:0] AH01071: Got error 'property Configs::$auth_method is deprecated in /path/to/phpicalendar/default_config.php on line 65; PHP message: PHP Deprecated:  Creation of dynamic property Configs::$ftp_server is deprecated in /path/to/phpicalendar/default_config.php on line 68; PHP message: PHP Deprecated:  Creation of dynamic property Configs::$ftp_port is deprecated in /path/to/phpicalendar/default_config.php on line 69; PHP message: PHP Deprecated:  Creation of dynamic property Configs::$ftp_calendar_path is deprecated in /path/to/phpicalendar/default_config.php on line 70; PHP message: PHP Deprecated:  Creation of dynamic property Configs::$salt is deprecated in /path/to/phpicalendar/default_config.php on line 71; PHP message: PHP Deprecated:  Creation of dynamic property Configs::$unique_colors is deprecated in /path/to/phpicalendar/default_config.php on line 77', referer: https://www.cs.ubc.ca/local/phpicalendar/week.php?cpath=&getdate=20250325&cal%5B%5D=Some_User

https://wiki.php.net/rfc/deprecate_dynamic_properties has information about possible changes to resolve the deprecations.