`org plan select` improvements

[CodingDoug]

• Consider changing the name to org plan switch to match org switch
• On macOS, the menu to select the plan rings the terminal bell on every up/down keypress. It should probably be entirely silent.
• Show some feedback about which billing method was used. Also add some feedback/help on how to make sure the user knows what to do to select the correct payment method in the event that they have multiple registered (Does it always take the default every month? No idea.)
• "Changes will effectively take place at the beginning of next month." - this should give an exact date/time with no ambiguity