Split sonar.log into 4 logs files specific to each JVM

Instead of all logs from the SonarQube JVMs beeing stored in the single sonar.log, each JVM should store log into its specific file:

• Main JVM (app) : sonar.log
• Web JVM (web) : web.log
• Compute Engine JVM (ce) : ce.log
• Elastic Search JVM (es) : es.log

All files will use the same rotation policy defined by sonar.log.rollingPolicy.
The max file policy (sonar.log.maxFiles) will apply to each file and not globally.