Tomcat uses the strings “on” and “off” to enable and disable
compression. YAML interprets on as true and off as false, leaving
ServerProperties.Tomcat.compression configured with “true” and “false”
respectively. One solution is to use “on” rather than on and “off”
rather than off in the YAML file but users may not realise that they
need to do so.

This commit updates the connector customiser that configures compression
to map “true” to “on” and “false” to “off”.

Closes gh-2737