Use queue and delay to process requisition

Like when confirming a purchase, the requisition should use the queue and the same delay.

assigned to @ced

added purchasing type::feature + 1 deleted label

New review265291002 at https://codereview.tryton.org/265291002/#ps279241002

added 1 deleted label and removed 1 deleted label

review265291002 updated at https://codereview.tryton.org/265291002/#ps269361002

review265291002 updated at https://codereview.tryton.org/265291002/#ps265311002

New changeset d0ded81a618b by Cédric Krier in branch 'default':
Allow to reset to draft approved but not processed requisition
https://hg.tryton.org/modules/purchase_requisition/rev/d0ded81a618b

added 1 deleted label and removed 1 deleted label

closed

New changeset 6368370f633f by Cédric Krier in branch 'default':
Allow to reset to draft approved but not processed requisition
https://hg.tryton.org/tryton-env/rev/6368370f633f