This function takes currency exchange rates data as input and returns a
list of two strings containing the fastest and slowest growing currency
exchange rate in relation to Canadian Dollar.
The data provided contains currency code in the format FX***CAD,
the average exchange rate and the date.
Retrieve historical daily currency exchange rates data for Canadian Dollar
in CSV format from Bank of Canada website.The function pre-processes and
cleans the data to transform it into a more usable format.