Improve Typescript support - ex: Add Java.type definitions

[ThaDaVos]

Your Environment

• Version used: (e.g., openHAB and JS Scripting add-on version) 5.7.0
• Environment name and version (e.g. Chrome 76, Java 8, Node.js 12.9, ...): Typescript 5.6.2
• Operating System and version (desktop or mobile, Windows 10, Raspbian Buster, ...): Ubuntu

Currently when writing rules using Typescript certain types are missing - also it takes some time to get it to load the existing types.
But the thing missing most are the Java.* types and intellisense - currently I am running into issues as follows:

TypeError: invokeMember (includes) on java.util.ArrayList@6fddcfbe failed due to: Unknown identifier: includes: TypeError: invokeMember (includes) on java.util.ArrayList@6fddcfbe failed due to: Unknown identifier: includes

I am getting this when I use .includes on some metadata I retrieved with Item.getMetadata() - now I am trying to catch this error by firstly converting it from a Java type to a JS type - but this is only possible if it is a Java type so before doing that I am trying to check if it is - here lies the issue - there's no typing for the Java.* methods at all - not even in the source code here (or I looked over it).

So this feature request is all about improving the typing support for Typescript - or at least, adding the missing types