Enable the configuration of multiple properties files

Provide a configuration option in Tomcat 9 that enables a user to specify a number of properties files to ingest. The properties files should be ingested in a specified order. There should be a flag to determine if properties are set permanently when first ingested, or can be overwritten by values in property files later in the order. There should be a flag to determine if the properties are loaded before or after parsing the remained of the server.xml file.

The customer is trying to replace the functionality provided by TCServer.
https://tcserver.docs.pivotal.io/3x/docs-tcserver/topics/manual.html#adding-a-system-properties-listener