Adds a imap_group_id column to IncomingEmail to deal with an issue where we were trying to update emails in the mailbox, calling IncomingEmail.where(imap_sync: true). However UID and UIDVALIDITY could be the same across accounts. So if group A used IMAP details for Gmail account A, and group B used IMAP details for Gmail account B, and both tried to sync changes to an email with UID of 3 (e.g. changing Labels), one account could affect the other. This even applied to Archiving!
Also in this PR:
* Fix error occurring if we do a uid_fetch and no emails are returned
* Allow for creating labels within the target mailbox (previously we would not do this, only use existing labels)
* Improve consistency for log messages
* Add specs for generic IMAP provider (Gmail specs still to come)
* Add custom archiving support for Gmail
* Only use Message-ID for uniqueness of IncomingEmail if it was generated by us
* Various refactors and improvements
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
Ignores the site setting "find_related_post_with_key" and always tries to honor the `In-Reply-To` and `References` header for emails sent to a group.
The senders email address must be included in the `To` or `CC` header of a previous email sent to the group and the `Message-ID` of that email must be included in the current email's `In-Reply-To` or `References` header.
Although 407a23663d will send rejection
messages for unrecognized errors, sometimes processing the email will
raise an error which has a blank message.
This commit:
1. Shows rejected emails which have already been processed and contain
a blank error in /admin/email/rejected
2. Replaces new blank error messages with the error type
