adds logback context properties to the extras

Currently the extras for logback only contain the thread specific properties stored in the MDC map. The "global" properties stored in the context (```LoggerContextVO```) are not put into the extras.

This pull request adds those properties to the extras which are being submitted to sentry. In case of a conflict in the keys between the context and the mdc the mdc properties take precedence over the context, because they are more specific.