Properly remove email notification on signout.

no ref
- Calls notifications.clear() on signout
Disable user settings autocomplete in Chrome

Closes #3271

- Adds 2 hidden inputs at the top start of the form that trick chrome into filling those, leaving out the rest.
User API ability to filter users by role

refs #3446

- This only covers the API changes needed for #3446
Disable autocomplete for setup & signup screens

No issue

- Adds 2 hidden inputs at the top start of the form that trick chrome into filling those, leaving out the rest.
Stop validation error notification stack

closes #3383
- Calls closePassive() if a new validation error is thrown to display
only the latest validation error
Merge pull request #3455 from ErisDS/issue-3446

User API ability to filter users by role
Transfer ownership end point

closes #3426
- added transfer ownership endpoint
- added owner to roles.permissible
- manually removed owner from roles.browse
- removed hard coded author role
- fixed tests that were passing due to hard coded author role
- added testUtils.setup(‚roles‘)
Perform a hard refresh upon signout.

Closes #3458.
Fix unhandled exception

no ref
- return result of mail.send
Merge pull request #3449 from felixrieseberg/iss3383

Stop validation error notification stack
Merge pull request #3453 from PaulAdamDavis/3271-prevent-website-autofill

Disable user settings autocomplete in Chrome
Merge pull request #3454 from halfdan/signout-email

Properly remove email notification on signout.
Merge pull request #3456 from PaulAdamDavis/prevent-auth-autocomplete

Disable autocomplete for setup & signup screens
Merge pull request #3457 from sebgie/issue#3426

Transfer ownership end point
Merge pull request #3463 from rwjblue/hard-refresh

Perform a hard refresh upon signout.
Merge pull request #3461 from halfdan/unhandled-rejection

Fix unhandled exception
Add User Role Dropdown

Closes #3402, Closes #3428

------------------

 ### Components
- Added GhostSelectComponent to handle async select creation (h/t @rwjblue)
- Added GhostRolesSelector (extends GhostSelect) for displaying user role options
- Created StoreInjector for surgically inserting the store into things that normally wouldn't have them.

 ### Users Settings
- InviteNewUserModal now uses GhostRolesSelector & defaults to Author
- The role dropdown for user settings has permissions set per 3402

 ### User Model
- Added `role` property as an interface to getting and setting `roles`
- Refactored anything that set `roles` to set `role`
- isAdmin, isAuthor, isOwner and isEditor are all keyed off of `role` now

 ### Tests
- Added functional tests for Settings.Users
- updated settings.users and settings.users.user screens
- fix spacing on screens

 ### Server Fixtures
- Fixed owner fixture's roles