First version of SmeftFR converter

[DavidMStraub]

This is the first version of a converter script to convert WCxf files to param_card.dat files for SmeftFR, just like in the case of SMEFTsim. Usage:

wcxf2smeftfr my_wcxf.json --output param_card.dat

[coveralls]

Coverage decreased (-1.5%) to 64.405% when pulling 773643e on smeftfr into 15bf66b on master.

[coveralls]

Coverage decreased (-1.5%) to 64.405% when pulling 773643e on smeftfr into 15bf66b on master.

[coveralls]

Coverage decreased (-3.001%) to 62.939% when pulling 4bb1031 on smeftfr into 15bf66b on master.