4.8.4: New validation rules (might be a breaking change)

What's Changed

• Added more validation rules to the names of Nodes and Ports.
• Fix XML validation to prevent two "fullpaths" to be the same. Some users might need to update their XML.
• More complex Groot2 publisher example to reproduce the issue with arrays in the blackboard.
• Added a new command line tool to generate the XML model file that Groot2 needs.
• Some improved documentation