Vega Exposure to Variance Unit Order Size Translation

This translation functionality is for the user that wishes to answer the question "What is the variance unit order quantity that corresponds to a target exposure expressed in vega units?".

This translation uses Equation 4 directly. The user provides the desired vega as position dollar PNL sensitivity per change in implied volatility of one percentage point, and the desired volatility level (σ^*_n). Equation 4 is used to compute the associated order size in variance units.