There is certainly an API to do it built into the server! It's an XMLRPC API, which has a bit more of a "barrier to entry" than a regular console (i.e. you can't just connect to it in-game), but is
very easy to use with various scripts
Here's the full methods list of commands you can send:
http://methods.xaseco.org/methodstm2.php
Presumedly, when a game is ready, the bot could send a request to the API to SetServerPassword("some-randomly-generated-password"). Once the match has ended (which the bot can receive an event for, using either the ManiaPlanet.EndMap or ManiaPlanet.EndMatch
callbacks), it can then send a SetServerPassword("") request to remove the password.
You could also conceivably allow the players to choose a map, choose the # of matches to play, choose game settings, etc. With the ManiaPlanet server API, the possibilities are quite endless
