add a `[p]adventureset delete` command to delete a users profile

[Drapersniper]

closes #367

[aikaterna]

It seems like this idea may already be implemented in adventureset clear?

[Drapersniper]

Probably too many commands to keep track of

[Drapersniper]

adventureset clear only resets the character sheet - this commands trully wipes all the users data (currency and potentially other things in the future) due to it calling adventureset_delete