add config checks for Apple Mail

[kristovatlas]

Need to handle both PGP users and non-PGP users.

• General
  • [ ] Add invitations to Calendar: Never (recommended)
• Accounts
  • [ ] for each account: SSL enabled (required)
  • [ ] for each account: Allow insecure authentication disabled (required)
  • Junk Mail
  • [x] Enable junk filtering
  • [x] When junk mail arrives, move it to the Junk mailbox (recommended) -- this will kill some phishing attacks
  • [ ] Disable exempting junk when message is addressed using my full name (recommended)
• Viewing
  • [x] Disable load remote content in messages (Required)
• GPGMail
  • [x] Encrypt drafts (required)
  • [x] Encrypt new messages by default (recommended)
  • [x] Sign new messages by default (recommened)
  • [x] Automatically check for updates (required)
  • [ ] Download updates automatically -- this is debatable of course, but best option for majority of users I think