Pull request dans le cadre d'un cours de génie logiciel

[MerceretF]

Pull Request

This PR fixes some code smells and minor issues

Changes proposed in this pull request:

• Some explicit private constructors to overwrite implicit public ones created automatically by java
• Constants for strings that are repeated more than twice
• Some comments to justify empty methods
• Refactor of the connect() method in CoreHandler.java
• Merging ifs that don't need to be apart
• Deleted unused commented out code lines
• Proposition to create LaunchErrorException to replace Exception in Launcher.java
• Renaming "name" to "keyName" in PersistableAttributeStore.serialize() to avoid confusion with PersistableAttributeStore.name
• Putting duplicated code from InboundHandshake.java into an auxiliary function to avoid duplication
• changing from replaceAll method to replace since not using regex in LoggerConstectFilter.init() for optimisation purposes