This is a major breaking change that moves away from having the
entire app configuration in external TOML files to settings being
in the database with a UI to update them dynamically.
The app loads all config into memory (app settings, SMTP conf)
on boot. "Hot" replacing them is complex and it's a fair tradeoff
to instead just restart the application as it is practically
instant.
A new `settings` table stores arbitrary string keys with a JSONB
value field which happens to support arbitrary types. After every
settings update, the app gracefully releases all resources
(HTTP server, DB pool, SMTP pool etc.) and restarts itself,
occupying the same PID. If there are any running campaigns, the
auto-restart doesn't happen and the user is prompted to invoke
it manually with a one-click button once all running campaigns
have been paused.
- Clean up main.go (by moving init to init.go) and improve
composition comprehension.
- Refactor app context and init struct and field names.
- Update package dependencies in initialisation.
This commit introduces a `blobstore` package and refactors the existing
upload mechanism. Upload is now handled by `providers` and the two
bundled providers are `S3` and `Filesystem`. `app.Blobstore` initialises
the correct provider based on the configuration and handles `Put`,
`Delete` and `Get` operations.
- Toggle options to enable self-service data export and wipe
options on the public unsubscription page. Subscribers can get
a copy of all data on them e-mailed to them as JSON, or
instantly wipe all their data.
- Refactor "unsubscribe" pages and URIs to "subscription".
- Add export icon to subscriber admin view.