WFLY-2850 External authentication (includes Undertow 1.0.6.Final)
Merge pull request #6180 from stuartwdouglas/WFLY-2850

[8.1.0] WFLY-2850 External authentication (includes Undertow 1.0.6.Final)
Move syslog4j dependency to the test suite.
[WFLY-3275] Make log4j a test only dependency.