MQTT Engine certificates fail to load on startup

This is a known issue with release 4.0.26 and is fixed in the current nightly build

The current workaround, which does not require changes to the MQTT Engine configuration, is described below:

Add the CA cert chain to the <ignition_install_folder>/data/certificates/supplemental directory
- Supported formats are DER encoded binary X.509, and Base-64 encoded X.509 (PEM-encoded ASCII)
Restart the Gateway so that the certificates can be used as 'trusted'.

The certificate can remain in the supplemental directory once the nightly or release 4.0.28 or newer is installed

This workaround will not work for certification based authentication