refactor: Replace System.out/err with proper Eclipse logging

[Artur-]

• Created VaadinPluginLog utility class for centralized logging
• Replaced all System.out.println with appropriate log levels (info/debug)
• Replaced all System.err.println with VaadinPluginLog.error
• Replaced e.printStackTrace() with proper exception logging
• Uses Eclipse ILog framework for proper plugin integration
• Maintains same message content with appropriate severity levels

[MarcinVaadin]

Why not use ILog directly?

ILog.get().info("Starting");
ILog.get().error("Generating template failed!", e);
ILog.get().warn("Creating a warning..");

according to https://www.vogella.com/tutorials/EclipseLogging/article.html each plugin should have own logger.

[Artur-]

You're absolutely right! The ILog.get() approach is much simpler and is the modern Eclipse way since Eclipse 2021-03.

[Artur-]

Updated

[MarcinVaadin]

Do we need static logger class? I meant that we can use ILog.get() everywhere in code instead of VaadinPluginLog...

[Artur-]

We can, but ILog.get() does not have any debug method which is why there is a logger class

[MarcinVaadin]

Indeed, no debug :-/ so let's keep as proposed.