[WFLY-543] : Provide an operation to request service status report after server has been started

Adding the new command "read-boot-errors" available from core-service=management to list all operations that failed during boot.
It displays all boot errors with the failed operation and the failure description / exception of the error.
Jira: https://issues.jboss.org/browse/WFLY-543
Why is this method (new param) necessary? Can't the existing constructor just create the BootErrorCollector itself? I may have missed it but I didn't see any place where a BootErrorCollector was constructed and then a ref to that object was needed by the code that constructed it.