Minor improvements

[ecarriou]

• [x] fix issue with $ in name
• [x] filter log messages
• [x] add check on system we delete if it is an extension that had been installed
• [x] update message when we delete a system that was already installed as extension
• [x] add a message when too much component to show
• [x] improve Create a model from JSON file extension
• [x] help box messages must be on all kind of screens