As a user, I want the ability to delete my list (from local storage)

[zeeatwork]

In the app's current implementation, we save a token 'permanantly' in localstorage. This can cause a few bugs:

• If the user receives another token for a shared list, they cannot return to the 'enter a token' homepage
• Users cannot have multiple lists
• if the primary user deletes all items from an existing shared list, the token no longer persists. Any secondary users will receive a 'token does not exist' message