add_current_datetime_column: Add current date and time to data frame.
Description
This function adds a new column to a data frame with the current date and time.
The name of the new column is a combination of the provided prefix, stage, and "Date_time".
If the new column already exists, it will be overwritten.
Usage
add_current_datetime_column(data)
Value
Data frame with an additional column containing the current date and time.