Select project group at startup

### Description

Netbeans support so called „project groups“ which is very handy, but when I open NetBeans with not preferred project group, it took so many time to switch to another.

### Use case/motivation

It will be very useful to have a possibility to choose the project group before whole NetBeans start.

So when the user have more than one project group defined, the dialog window

should be displayed before projects are loaded (in the startup phase).

Or when somebody run the NetBeans with some argument like `--manage-group`

### Related issues

_No response_

### Are you willing to submit a pull request?

I want to, but I'm not a Java developer

### Code of Conduct

Yes

Begin by tracing NetBeans startup and the existing project-group dialog behavior; the issue provides no file or test entry point. Completion means allowing a project group to be chosen before projects are loaded, including the proposed --manage-group startup path.

Written by the indexing model from the issue text.