jsreport extension adding support to combine one template from multiple sub templates

See https://jsreport.net/learn/child-templates

• internal changes to support new response.output api

• minimum node.js version is now 18.15.0

• improve logging and errors

• changes to enable caching of system helpers

• update deps to fix npm vulnerabilities report

Initial release for jsreport v3 New templating engine helpers introduced

{{#childTemplate pathOrName}}