Automated initialization method for Costing Blocks

[andrewlee94]

As part of the improvements to the IDAES Costing Framework, we realized that for most costing Blocks it should be possible to automate initialization by doing a block-triangularization of the Block in order to determine the initialization order and to then sequentially solve the constraints in order.

[andrewlee94]

@Robbybp Just a reminder of this - I am actually wondering if we should try to make this a global tool (as a default option for all models).

[Robbybp]

Yes, I would like to try and implement something general for initialization via a block-triangularization. Ideally this would be faster than current initialization, but possibly less reliable for certain models/definitions of reliability (although possibly more reliable). I think it would be nice to use the performance suite to benchmark initialization times with such a strategy.

[andrewlee94]

This will be captured as part of #735.