Improved support for search criteria

[deosrc]

• Adds an option to specify a custom search criteria
• Fixes mail being processed multiple times if flag is not "SEEN"
  • Search was always looking for "unseen" mail. If the mail flag was not set to seen, the mail would remain unread and be processed next run. A suitable filter should now be determined, or an error raised if the user must specify one.
• Remove "DRAFT" flag option
  • Causes strange behaviour where inbound mail can be converted to an outbound draft. This can then be accidentally discarded deleting the original message or converting it back can result in the metadata of the email being lost.
• Add "UNFLAGGED" mail flag option
  • Removes the "FLAGGED" option from the message once processed

[rob-luke]

Thanks for the contribution @deosrc Can you get the formatting tests to pass then I can try this locally (currently I have no automated testing). Sorry for the delay getting back to you, I have been on holidays.

[deosrc]

Sorry for the delay getting back to you, I have been on holidays.

No problem. Hope you had a good time.

Formatting should now be correct and auto-formatting enabled for VSCode.

[rob-luke]

Again, sorry for the delay here @deosrc I plan to hack on this a bit myself in the coming weeks, so please highlight any other issues you find.