Better menu (is less menu)

Our left menu has become well filled. I often found that users are a little bit lost in it because they have many levels opened and because there are entries they do not care.
Our solution for now is to advise to use the favourites. But it is not ideal and neither good for the first experience.

I propose to restructure the standard menu to have only 2 levels and to forbid to have action on menu entry that have children (it is hard to understand and to only open the folder without launching the action).
For that I propose:

• To move all configuration menu entries under a single toplevel "Configuration" and each entry is named after their "module".
• Add an exception for "Administration" with 2 levels
• Move out of "Financial" as toplevel: "Invoices", "Payments", "Statements"
• Whenever possible remove menu entry in favor of button on configuration (ex: Financial template could be accessed from the financial configuration)
• Have a single reporting menu entry per "module" which point to multiple actions to choose (except for Financial which are not considered as reporting)
• Have a single menu entry for tree and list (ex: Parties Categories) by allowing to switch on the same window
• Use one (2 for label) column for all configurations without separator (it is often break by extension)
• Limit to open only one root entry at a time