Use fontawesome to show membership auto-renew status and and error indicator

This changes the membership tab to use fontawesome for the auto-renew "tick" and adds an exclamation mark when auto-renew is enabled but the subscription has been cancelled.  Before, a membership with cancelled recurring contribution looked like it had no auto-renew enabled, but in reality it did.  Now an exclamation mark shows that it is different from a membership that has no linked recurring contribution.