Favor "include" records for toolboxes know to the ToolboxRegistry

[benjamin-heasly]

We have some configurations in the ToolboxRegistry that contain duplicate records, for toolboxes that are already known to the registry.

For example, the isetbio configuration contains a record for the UnitTestToolbox, which points at the UnitTestToolbox git repository.

But UnitTestToolbox is already known to the registry, with its own configuration that points to the same place.

Instead of duplicating this information, the isetbio configuration should refer to UnitTestToolbox with an "include" record that can be resolved to the already-known UnitTestToolbox configuration. For example:

{
    "name": "UnitTestToolbox",
    "type": "include"
}

Some reasons why including already-known configurations would be good:

• it would be DRY
• it would allow projects like UnitTestToolbox project to change its own configuration without having to update other configurations that use UnitTestToolbox
• it would allow projects like UnitTestToolbox to be resolved along with any dependencies for other configurations that use UnitTestToolbox

We should review the registry and update configurations so that toolboxes known to the registry are referred to as "include" records.

[DavidBrainard]

I did some of this, but need to make sure it is all done before closing.