This adds beginning email subscription functionality, with only MySQL support,
Mailgun support, and incomplete support for private instances. It includes
database changes, so run:
writefreely db migrate
to use this feature.
Ref T856
- Adds a new interface, Apper, that enables loading and persisting
instance-level data in new ways
- Converts some initialization funcs to methods
- Exports funcs and methods needed for intialization
- In general, moves a ton of stuff around
Overall, this should maintain all existing functionality, but with the
ability to now better manage a WF instance.
Ref T613
