Embed or attach files based on their file extension:
* Set 'Content-Disposition: inline' for images
* Set 'Content-Disposition: attachment' for other files
* Refactoring servers to support custom workers and graceful shutdown.
* Refactoring workers to support custom mailers.
* Refactoring mailer to be an interface, with proper instances instead of a single global instance
* Cleaning up a few things. Locking maillogs for campaigns set to launch immediately to prevent a race condition.
* Cleaning up API middleware to be simpler
* Moving template parameters to separate struct
* Changed LoadConfig to return config object
* Cleaned up some error handling, removing uninitialized global error in models package
* Changed static file serving to use the unindexed package
This builds on the work from @c-f in #1090 to fully add support for "timed" campaigns, in which the emails are spaced apart as opposed to all being sent at once.
Added the modified_date field to results so it's easy to keep track of the last results that were modified without having to parse every event. Updated the tests to reflect the changes.
