196 gui kernel

This merge requests is the beginning of the gui component of the DFSS client.

• It adds several makefile instructions to build the gui with docker on linux, but these instructions and the gui code are ignored by the CI
• It adds two screens for the GUI: registration and authentication
• GUI configuration is stored in $HOME/.dfss directory

For testing this MR, please try to:

• Compile the GUI on your computer using the provided docker commands:
  • make prepare_gui
  • make gui
• Test it
• Open .ui files with QtCreator