* add drafts.json endpoint, user profile tab with drafts stream
* improve drafts stream display in user profile
* truncate excerpts in drafts list, better handling for resume draft action
* improve draft stream SQL query, add rspec tests
* if composer is open, quietly close it when user opens another draft from drafts stream; load PM draft only when user is in /u/username/messages (instead of /u/username)
* cleanup
* linting fixes
* apply prettier styling to modified files
* add client tests for drafts, includes a fixture for drafts.json
* improvements to code following review
* refresh drafts route when user deletes a draft open in the composer while being in the drafts route; minor prettier scss fix
* added more spec tests, deleted an acceptance test for removing drafts that was too finicky, formatting and code style fixes, added appEvent for draft:destroyed
* prettier, eslint fixes
* use "username_lower" from users table, added error handling for rejected promises
* adds guardian spec for can_see_drafts, adds improvements following code review
* move DraftsController spec to its own file
* fix failing drafts qunit test, use getOwner instead of deprecated this.container
* limit test fixture for draft.json testing to new_topic request only
- Renamed 'stream-item' component to 'user-stream-item'
- Replaced generic 'item' class with clearer 'user-stream-item' class
- Retained 'item' class for backward compatibility, marked as 'DEPRECATED'
- Extracted CSS pertaining 'user-stream-item' component to component CSS files
- Removed unnecessary duplication from 'user-stream-item' CSS
- Removed unnecessary nesting from 'user-stream-item' CSS
