Make CollecTor operators aware of logging
The logging framework configuration should be decoupled from CollecTor, i.e.
- remove default logback.xml from
collector-<version>.jar - add an example of logback.xml to src/main/resources
- provide the two
logback-{classic,core}.jars with a release, but remove them fromcollector-<version>.jar - add more logging info to the operating guide
The goal should be to make operators aware of the logging choices and their responsibilities. Without a default logging setup operators will have to think about choices like
- logging framework implementation
- log-level settings
- logging environment, e.g. path settings etc.
Once an instance is configured these logging settings won't just change magically with the upgrade to a new release and thus issues like legacy/trac#20079 (moved) will be avoided.