Improve the add_item method

[JoelMon]

In the add_item method there's these [two for loops]:(https://github.com/TheoDevelopers/pyTalkManager/blob/setup-brotherDB-read-write/db.py#L98):

for each_column in column:
    list_column = list_column + each_column + ', '

for each_value in value:
    list_value = list_value + each_value + ', '

Those two for loops can be boiled down into one method inside of add_items that accepts data in a list and returns a properly formatted string ready to be used.