[12757]  Chat commands disabled for normal players.

A new setting for the world server has been added. From now on
chat commands executed by normal player accounts will no longer
be executed, unless you explicitly enable the `PlayerCommands`
option.

By default player command execution is disabled.

commit is based on https://github.com/mangoszero/server/commit/208599f7fa5b1b55e722d65e665d2fc4c671d037