Improve mobile and tablet compatibility

[madmath03]

✨ There are many aspects that should either be fixed or improved for a better mobile / tablet experience.

Here is a summary of everything I found so far that could / should be done (list may increase):

• the logout link is only displayed when mouse hovering the user name link... hard to do on devices without a cursor. We should be able to access logout link by clicking on a button to popup the logout link
• the side menu takes a lof space which would be really needed on small devices. Having the side menu act like a drawer which can be hidden/displayed would help quite a lot.
• the main menu will not display icons on mobile but only the text. This was the desired behavior but having only the icons would actually be more space efficient and probably easier to remember.
• the main menu will overflow on several lines if there are too many modules to display. Having a "More..." button with a popup displaying the additional modules would be more efficient. Actually, this behavior would be interesting for any device and might make more sense to be part of Dolibarr itself.