Generates contents using Apache FreeMarker.
Configuration shall be a map which supports the following keys:
base- Base URL for resolving templates. The base itself is resolved to the loading base. When loading from a URL the loading base is the URL of the YAML specification file. If not specified, then the loading base is used as templates resolution base.
template- Template to render.
model- Context property of model object to use for template rendering. If not provided then the context itself is used as the template model.
free-marker: base: free-marker-templates/ template: hello.ftl