JSLT enabled by default

As of version 2001, JSLT for the REST layer of headless server, is enabled by default.

(CMS-16476)

REST query mapping now configurable

The resource file containing the rest query mapping is now configurable by the application property 'caas-rest.query-mapping-pattern'. The default resource file was moved from resources/query-mappings.properties to resources/graphql/rest-mapping/simple-mapping.properties. By default, all properties files in that folder are considered to contain query mappings.

(CMS-16233)