Review area name validation

[patak-dev]

We are converting to valid a valid css name when generating the code or showing the area name in the editor.
Now that we are also converting to a valid name on user input and not accepting spaces anymore, we could remove refactor the state to trust that it will always be a valid name and avoid having to convert everywhere. It would also be good to add dashes when the user press the space key (in the Code inputs and in the Area Selection name input).