This feature can be enabled by choosing a destination for the
`shared drafts category` site setting.
* Staff members can create shared drafts, choosing a destination
category for the topic when it is published.
* Shared Drafts can be viewed in their category, or above the
topic list for the destination category where it will end up.
* When the shared draft is ready, it can be published to the
appropriate category by clicking a button on the topic view.
* When published, Drafts change their timestamps to the current
time, and any edits to the original post are removed.
* only toggles
* fix a bug with presence
* more tests
* do not duplicate `continuing discussion...` text
* persist state to allow switching between toggles
Allow users to access different reply modes from the composer.
Actions introduced:
- reply_as_new_topic
- reply_as_private_message
- reply_to_topic
- reply_as_whisper/not
