Handling of user provided contest rule and multiplier files

[dl1jbe]

From time to time users provides contest files (rules and multipliers) for new contests. We may be not able to confirm the correctness of the files in short time. But it seems to be good to incorporate these contest into the distribution.

I would suggest to somehow mark these files as 'not officially' provided. The following ideas comes into mind:

• Add an additional directory 'user_provided' into the distribution and place all relevant files there.
• Store them on the wiki (would need an additional download, but could be managed by the users themself)
• At least add some comment lines stating the files are user provided and give information about author and date