Respect the system colour scheme (day/night mode)

### Description

The operating system allows you to automatically switch the day/night schedule depending on the time. Modern applications can automatically react to this and switch the colour scheme themselves.

For example, the Visual stuid code tool enables this functionality by enabling the `window.autoDetectColorScheme` parameter, see https://code.visualstudio.com/docs/getstarted/themes#_automatically-switch-based-on-os-color-scheme

I understand that in NetBeans it is not possible to fully switch the color scheme without restarting, but it would still be IMHO possible to have a preferred "light" and "dark" scheme set and use it when starting/restarting the application.

It wouldn't be fully automatic, but it would just be enough to turn the app off/on... And it would just launch straight away in the correct mode on startup, so when switching from work to home it would actually be fair enough :)

### Use case/motivation

Using a bright environment in over-lit offices is more readable and less taxing on the eyes, while running Netbeans in white mode at night is like lighting a flashlight :)

### Related issues

_No response_

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

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

No NetBeans files or tests are named. Start by examining how NetBeans selects its color scheme during startup, then review the linked Visual Studio Code OS-scheme behavior as a comparison. Done means the application can retain preferred light and dark schemes and starts in the appropriate one based on the system scheme, without requiring fully live switching.

Written by the indexing model from the issue text.