Better UTF-8 properties files support

### Description

I've hoped, that properties files would be UTF-8 by default in Java 18. This didn't happened.

current situation:

- Default character set in Java 18 is UTF-8
- Java properties files (with translated texts) are still by default in ISO-8859-1 in Java 18
- There is option in Netbeans to use UTF-8 properties files - **Use project encoding** checkbox

Would it be possible to improve handling of UTF-8 properties files? Biggest problem seems to be that checkbox settings is stored in local netbeans folder (~/.netbeans/14/var/attributes.xml) not in project folder. So every team member has to configure it himself. It doesn't make sanse for each team member to have different settings.

### Use case/motivation

_No response_

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow the Apache Software Foundation's [Code of Conduct](https://www.apache.org/foundation/policies/conduct.html)

Start by examining NetBeans' “Use project encoding” checkbox and how its setting is stored in ~/.netbeans/14/var/attributes.xml. Trace where Java properties-file encoding is selected, then define and verify project-level behavior so team members receive consistent UTF-8 handling.

Written by the indexing model from the issue text.