AT

• Add Graal.js script engine to the distros (CE and EE including Run) - do not add it as a transitive dependency to the core and Spring Boot Starter
• Make Graal.js the default JS script engine in the engine
  • Fallback to whatever JS script engine is present if Graal.js is not available
  • Make the JS script engine configurable, so users can still choose anything else
• Investigate incompatibilities with Nashorn
  • document unresolvable ones
  • try to provide a solution for solvable ones (e.g. directly or by configuration option or Nashorn compat mode)
  • candidates:
    • public method/attribute access only in Graal.js
    • loading external script files from JS with "load"
• Test coverage
  • JS script tests default to Graal.js
  • add explicit Nashorn tests to ensure compatibility - exclude those on JDK15+