Currency rate cover

** The most critical part of the code was changing the currency or cryptocurrency value from the different select field. Since the data for the exchange rate were saved in an array of objects, and the options for the select field were gotten by mapping the exhange data array and rendering the different names. However selecting an option doesnt change the state for convert-to and convert-from in the adequate way without an error. As such, the exhange data array had to be looped through and each individual option name compared with the update from event.target.value for each of the select field and if it matches, the state for convert to and convert from is update with the apropraite object and the ids in the API url updated appropraitely.