To do: Select leagues needs to be a separate function

[Pringleman83]

The select_leagues function needs to be separated so that there is a separate function for the selection of leagues only. The new function needs an extra argument for whether multiple selection is allowed. This could be set by default to True or False.

I expect it will only be necessary for it to take the available leagues list and optional Boolean value for multi and it will return the selected league(s). The format of the returned item will need some consideration of other functions. Ideally, It'll always be a list, even if the list only contains one item. It may be necessary to edit dependant functions to make this work though.