If sfc_name is the active then the new sfc column replaces it and becomes the active one.
Arguments
- x
 The object.
- coords
 A character vector of specifying the two columns with the point information.
- crs
 An integer with the EPSG code, or character with proj4string.
- sfc_name
 A string of the name of the sfc column to create.
- activate
 A flag indicating whether to activate the sfc.
- retain_orig
 A flag indicating if the input coordinates should be retained as columns in the dataframe.