Add additional variables to CERF output file

[kmongird]

The following variables from the NLC calculation should be added to the output csv file.

• discount_rate
• annuity_factor
• levelization_factor_vom
• levelization_factor_fuel
• levelization_factor_carbon

Additionally, they should be added to the documentation in the key outputs table https://immm-sfa.github.io/cerf/user_guide.html#key-outputs

Name	Description	Units
discount_rate	interest rate used to determine the present value of future cash flows	N/A
annuity_factor	factor used to determine the present value of an annual cost based on the life of the asset and the discount rate	N/A
levelization_factor_vom	factor used to determine the levelized variable operations & maintenance costs over the life of the asset	N/A
levelization_factor_fuel	factor used to determine the levelized fuel costs over the life of the asset	N/A
levelization_factor_carbon	factor used to determine the levelized carbon tax costs over the life of the asset	N/A