* Support for custom messages and redirects when creating posts
When a post/topic is created Discourse serializes a `NewPostResult`
object. Normally this contains a status like `created_post` or
errors describing why the post could not be created.
There are times when a plugin might want to take the inputted post
and do something in the background. In this case, the plugin
can return a custom `message` and `route_to` attribute in the
`NewPostResult`.
If present, the message will be displayed in an alert, and when "Ok" is
clicked the user will be routed to the new URL.
* Destroy the draft in parallel
Zeitwerk simplifies working with dependencies in dev and makes it easier reloading class chains.
We no longer need to use Rails "require_dependency" anywhere and instead can just use standard
Ruby patterns to require files.
This is a far reaching change and we expect some followups here.
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
