Allow to configure globalHubMode for SentryAppender from logback.xml

[marbon87]

Problem Statement

We have a java swing app, that uses logback for logging and the SentryAppender from sentry-logback. Sentry is configured in the logback.xml.

We need to enable globalHubMode, to get breadcrumbs across multiple threads. I didn't find a way to enable globalHubMode by using logback.xml. Only solution i found is to copy the content from SentryAppender#start()

Solution Brainstorm

Add the attribute globalHubMode in SentryAppender to get the possibilit of configuring globalHubMode from logback.xml