Enable Single Site mode

Enable 'Single Site' mode

In order to support projects based on version 13.0.0 and older, 'Single Site' mode should be enabled by using one of the options below:

• Set a Java system property use.hcm.sites to false. Using this option is most suitable during development mode.
  See Run and Develop with Cargo (section Pass System Properties) for instructions on how to add the system property to your Cargo development environment.

• Add an hcm.properties file in the cms/src/main/resources folder of your project containing a property use.hcm.sites set to false:

  use.hcm.sites=false

  This method is preferred in production environments and takes precedence over the previous one.