rotate logs in icecast container

[mcfiredrill]

If you docker exec into the icecast container on production, you'll see there are a huge amount of logs.

icecast@4b00337b2578:/usr/local/share/icecast/logs$ du -h .       
31G     

This causes the disk to fill up pretty often.
These need to be rotated properly by setting up logrotate in the docker image.