Solr start scripts -- only log to console when running in foreground

Currently the log4j.properties file logs to the console, and the start scripts capture console output to a logfile that never rotates. This can fill up the disk, and when the logfile is removed, the user might be alarmed by the way their memory statistics behave – the "cached" memory might have a sudden and very large drop, making it appear to a novice that the huge logfile was hogging their memory.

The logfile created by log4j is rotated when it gets big enough, so that logfile is unlikely to fill up the disk.

I propose that we copy the current log4j.properties file to something like log4j-foreground.properties, remove CONSOLE logging in the log4j.properties file, and have the start script use the alternate config file when running in the foreground. This way users will see the logging output when running in the foreground, but it will be absent when running normally.