Rely only on `Vector` in case `PartitionedVector` represent a `Vector`

In the case an `pv::PartitionedVector` has `pv.simulate_vector == true`, then try to use only the `Vector` `pv.epv.v`.
In that case, most operations must be reimplemented to distinguish the cases `pv.simulate_vector == true` and `pv.simulate_vector == false`.
Also, the broadcast mechanism must be adapted, such that either :
- broadcast between `PartitionedVector` and `Vector` is supported
- we identify first that all `PartitionedVector`s have `pv.simulate_vector == true` to then apply the broadcast on their respective `pv.epv.v`.