Update Fentanyl conversion factor to 2.4

[brynrhodes]

The current Opioid calculation logic uses 7.2 as the conversion factor for transdermal patch Fentanyl. This conversion factor is used for research calculations, the clinical calculation conversion factor should be 2.4, per the tables specified here: https://www.cdc.gov/drugoverdose/pdf/calculating_total_daily_dose-a.pdf

[brynrhodes]

Changing this conversion factor to 2.4 results in incorrect calculation of the MME value for Fentanyl patch, due to the fact that it is applied over 3 days. The 2.4 is appropriate for 1 day, but since dosing of the patch applies over 3 days, the conversion factor needs to be multiplied by 3 to apply correctly. Should this be done in the GetConversionFactor logic, or should the discrepancy be handled in the GetDailyDose calculation logic?