Capacity can be set on Computer Models and be eventually applied on Computers

This change aims prevent flood of request and looking for partitions ghosts when hosting has full capacity or allocation is not possible.

Also put out the speed hack from the core code.

It is assumed when arguments and config parameters are merged.
Otherwise, it is not possible to set this option from the .cfg.

Allows easier hack.

This reverts commit 7fe0677c.

This reverts commit 580ab267.

This reverts commit 0c552d82.

This reverts commit 06ebfdb7.

This reverts commit 7581e55e.

This reverts commit 4e428fdc.