[jsscriptingnashorn] JavaScript Scripting Nashorn Automation (#14013)

* [jsscriptingnashorn] JavaScript Scripting Nashorn Automation

This add-on allows you to use your older JavaScript (ECMAScript 5.1) rules on newer Java versions until they are migrated to JavaScript (ECMAScript 2021+).
The add-on uses a standalone [Nashorn Engine](https://github.com/openjdk/nashorn) which was part of Java until it was removed in Java 15.

* Update parent to 3.4.0-SNAPSHOT and nashorn-core to 15.4

For the Nashorn changelog, see:

https://github.com/openjdk/nashorn/blob/main/CHANGELOG.md

* Update parent to 4.0.0-SNAPSHOT
* Remove removeUnsupportedNashornArgs
* Update scriptTypes
* Add CODEOWNERS entry
* Recycle ScriptScopeOSGiTest.java

It got removed in openhab/openhab-core#2994

* Remove redundant new line from pom.xml

Signed-off-by: Wouter Born <github@maindrain.net>

CODEOWNERS

@@ -8,6 +8,7 @@
 /bundles/org.openhab.automation.groovyscripting/ @wborn
 /bundles/org.openhab.automation.jrubyscripting/ @boc-tothefuture @ccutrer @jimtng
 /bundles/org.openhab.automation.jsscripting/ @jpg0 @florian-h05
+/bundles/org.openhab.automation.jsscriptingnashorn/ @wborn
 /bundles/org.openhab.automation.jythonscripting/ @openhab/add-ons-maintainers
 /bundles/org.openhab.automation.pidcontroller/ @fwolter
 /bundles/org.openhab.automation.pwm/ @fwolter
@@ -414,6 +415,7 @@
 /bundles/org.openhab.voice.voicerss/ @JochenHiller @lolodomo
 /bundles/org.openhab.voice.voskstt/ @GiviMAD
 /bundles/org.openhab.voice.watsonstt/ @GiviMAD
+/itests/org.openhab.automation.jsscriptingnashorn.tests/ @wborn
 /itests/org.openhab.binding.astro.tests/ @gerrieg
 /itests/org.openhab.binding.avmfritz.tests/ @cweitkamp
 /itests/org.openhab.binding.feed.tests/ @svilenvul