Restore HTTPSConnectionWithCLITestCase

HTTPSConnectionWithCLITestCase was removed as part of the WFCORE-5526 work. But downstream it has been adapted to be able to use a pure Elytron config, and there doesn't seem to be much coverage of CLIENT_CERT authentication to the management interface (which also involves SASL integration), so porting the downstream changes seems like a reasonable way to get coverage.