Better support of date and period for move template
As discussed https://discuss.tryton.org/t/template-move-and-dates
there is a conception bug in that the date of a move is not asked for by default even
though the period is, giving an error that the date is outside of the period if a
period other than the current period is selected.
This is because a blank date in the template is considered as 'today()'.
Meaning basically the design is primarily to use only the current period.
This is naturally a bogus assumption.
A work-around suggested was to use a keyword such as 'date' in order to select
a date in the period selected.
This is extremely awkward. There is no real context between the two forms asking
for the period then later asking for any date without being constrained to the period.
Both the date and period should be asked for in move_template_create_template_form,
permitting a reasonable interface to automatically select the period according to the date,
or if the period is selected first, then the date selection can be opened within the period selected.
This will make using the template much more intuitive.