project_mrp should not depends on mrp_jit

As I understand the workflow, the only purpose of mrp_jit for project_mrp is to immediatly create a new task after a sale order confirmation.

As a side effect, all other procurements are also affected by this functionality since all other procurements are now processed the same way: a purchase order is immediately created, a stock reservation is immediatly done, a production order is immediatly created.

To avoid this side effect and to keep current functionality, a condition should be added somewhere to allow immediate task creation via procurement without having to install mrp_jit