[gokz-global] Show warning when starting timer if globalcheck fails

[walliski]

There are multiple reasons why a server can fail the globalcheck that the user might not notice. Wrong map version, old plugins, changing map with wrong capitalization of the name, or issues with the global api. This can lead to players spending a lot of time grinding times without getting them stored to the Global API.

To make it clear for the players that the server is currently not in a global accepted state, it could show a warning in the chat when you start the timer: "Warning: The server did not pass the global check, only local times will save" or something. This functionality could be behind a cvar (default on), so that the warning message could be disabled in case you have a server with non-global maps.

To further avoid unnecessary spam, it could also check if the server is intended to be global or not, for example by checking that an API key exists, and potentially something more?