Update System Settings doc (.config files)

• Type: New Article
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 7.0.x
• Component/s: Product Team User and System Mngt
• Labels: None
• Git Pull Request: https://github.com/sez11a/liferay-docs/pull/2014

Referring to this documentation:

https://dev.liferay.com/discover/portal/-/knowledge_base/7-0/system-settings

While working on this ticket:

https://issues.liferay.com/browse/LPP-22136

One of our TSEs discovered that the .cfg file format cannot handle complex data types, and some of Liferay's portal properties are string arrays:

https://issues.apache.org/jira/browse/FELIX-4431

Therefore, we will need to update the documentation to discuss the .config file format, similar to what's documented here:

https://sling.apache.org/documentation/bundles/configuration-installer-factory.html

We will also need to export files as .config whenever there are string arrays and avoid using the .cfg format except when we know for sure that all property values are simple.