User Feedback - Unit mismatch!

#### Description:
At present it is not clear to users that their Rhino canvas must be in unit meters for LCA calcs to work properly, leading to inaccurate LCA.

#### Steps to reproduce:
Set up a millimeters based Rhino canvas and model a 1m3 box. For a material with a QuantityType of Volume and a QuantityTypeValue of 1, the GWP of that box should agree with the GWP of that EPD. Instead it is about ten orders of magnitude off due to the unit mismatch.

#### Expected behaviour:
At a minimum, user should have to select what units their document is in from an enum, and if its not in meters, Rhino should throw an error telling the user to change their document units. Even better would be a user enum that triggered autoconverts from the incoming units (enum lookup) to meters.

#### Test file(s):