Upgrade slf4j from version 1.7.7.jbossorg-1 to 1.7.22

There should no longer be a need for the forked version. The fix for SLF4J-167 should be in version 1.7.14 with some additional fixes for replaying the previously lost logs.

Quote from comment on JIRA

The problem of lost logs during initialization in a multi-threaded application is solved by storing and replaying the logs which would be otherwise lost. Fix available in SLF4J version 1.7.15.

Analysis will need to be done to ensure this works as expected before the fork is no longer required.