When moving some products between two warehouses thanks to an internal
transfer, the forecasted inventory becomes incorrect

To reproduce the issue:
1. In Settings, enable "Multi-Warehouses"
2. Let WH01 be the existing warehouse. Create a second one WH02
3. Create a storable product P
4. Update the quantity of P:
    - 3 in WH01/Stock
5. Create a planned and internal transfer T:
    - Source: WH01/Stock
    - Destination: WH02/Stock
        - Ignore the warning
    - Operations:
        - 1 x P
6. Mark T as todo
7. Open the Forecasted Inventory:
    - Filters:
        - Forecasted Stock
        - Product: P
    - Group By: Warehouse

Error: The report is incorrect, it says there are 3 P in WH01 and 0 in
WH02 (should be 2 and 1). It becomes worst if T is done (the quantities
in the past become incorrect)

We should be able to move a product between two warehouses thanks to an
internal transfer (so the warning of the step 5 should be removed).
Moreover, the `report.stock.quantity` should consider that use case.

When processing a stock move, the SQL view translates it as an in-move
or out-move for a specific warehouse. For instance, if the SM comes from
a warehouse and goes to a location without any warehouse (e.g., customer
location), the SM is considered as an out-move. But here is the issue:
in case of an inter-warehouse SM, both source and destination have a
defined warehouse.

Therefore, we need to:
- Duplicate the inter-warehouses SM (so we have one in and one out)
- Fake the values (no destination warehouse for the out move, no source
warehouse for the in move)

Also, before duplicating all SM, we filter out some useless SM:
- Draft and cancelled ones
- SM done more than 3 months ago (because the report only works for [-3
months; +3 months])

Considering some tests:
(SM are confirmed. Each test has been repeated 5 times to get an
average)
|                                       |          |
|:-------------------------------------:|:--------:|
| 5000 SM, 0% inter-wh, without the fix |  ~715 ms |
| 5000 SM, 0% inter-wh, with the fix    |  ~710 ms |
|                 Impact                |   0.99x  |
|                                       |          |
| 6666 SM, 0% inter-wh, without the fix |  ~911 ms |
| 5000 SM, 33% inter-wh, with the fix   |  ~999 ms |
|                 Impact                |   1.10x  |
|                                       |          |
| 7500 SM, 0% inter-wh, without the fix | ~1004 ms |
| 5000 SM, 50% inter-wh, with the fix   | ~1097 ms |
|                 Impact                |   1.09x  |

The impact is not that significant

OPW-2752017
task-2822157

closes odoo/odoo#91056

X-original-commit: b6833702
Signed-off-by: Arnold Moyaux <arm@odoo.com>
Signed-off-by: Adrien Widart <awt@odoo.com>