Hi L2 - Add L2 Map variables

[tmplummer]

Algorithm Description:

It is desireable to add the following variables to Map products:

• Counts 
• Background rates
• Background rate uncertainty
  • ena_intensity_background_systematic_err Background intensity uncertainty (Uncertainty in intensity due to background subtraction)
• ena_intensity_calibration_systematic_err (e.g. 40% of ena_intensity)
• We need to scale the systematic uncertainties by the the flux correction ratio