We add the valuation at date wizard by re-using the quantity at date
wizard and adding a context key to separate the both.
The same view/action is used when openning the current or at date
valuation, only the `to_date` context key is changed.
Kind of switches the behavior for inventory and valuation report,
meaning allows the user to see the quantity at date and disallow him to
see the valuation at date.
- Preserved explicit 3rd-party copyright notices
- Explicit boilerplate should not be necessary - copyright law applies
automatically in all countries thanks to Berne Convention + WTO rules,
and a reference to the applicable license is clear enough.
Simon Lejeune