Adding 'bets#show' content

This PR adds content for the 'bets#show' view page.

This PR does NOT address styling of the page. That will be separate.

cc @Clee681 @irmiller22 LMK what you think please
Yea, it doesn't feel great, but I can't think of a more elegant solution. I will suggest using the `current_user_role` in `current_user_win_amount_for` and `current_user_lose_amount_for`. Since `current_user_role` returns either "inviter" or "invitee", I think we can use dynamic dispatch to send the right method to bet. Example below:

```ruby
def current_user_lose_amount_for(bet)
  amount_at_risk = "#{current_user_role(bet)}_amount_at_risk".to_sym
  bet.send(amount_at_risk)
end
```
Note that I would move the `number_to_currency` call into the view.