Enable to choose explicit resource allocation in resource planning with pools

At present time, if a resource belongs to a resource pool and if it is allocated both as a unique resource and by the pool, its allocation in the resource planning is shown only for when it is allocated as a unique resource. The resource pool behave as a separate entity.

Proposed evolution : enable via a check box for example to show in the resource planning all his contributions, eitheir when allocated as a unique resource, either when allocated in resource pools.

Use case : analyse resource load.