Ultimate Parametric LACK Enclosure - height adjustable

Remix of the [Ultimate Parametric LACK Enclosure](https://www.thingiverse.com/thing:3188720) by BuzzAldrin.

I ended up not building the enclosure, so my modifications are **untested**.

I added an additional parameter: AdditionalHeight. This parameter controls additional height that is added to the top corner pieces.
I also modified the top receptors for the plexiglas to be the same size as the bottom ones.
The included stl files add an additional height of 40mm. Use the Fusion 360 model to create custom pieces with the desired height.

See the original thing for all details on this enclosure.