This commit provides the first part of the bulk import system.
The CLI command is provided, complete with validation & apply modes. All
the basic properties of Teams and Channels can be imported. Users &
Posts will follow separately in a future commit.
* Refactor and move session logic into app package
* Refactor email functions into the app package
* Refactor password update into app package
* Migrate user functions to app package
* Move team functions into app package
* Migrate channel functions into app package
* Pass SiteURL through to app functions
* Update based on feedback
* Add app package and move logic over from api package
* Change app package functions to return errors
* Move non-api tests into app package
* Fix merge
