* Implement POST /oauth/apps endpoint for APIv4
* Implement GET /oauth/apps endpoint for APIv4
* Implement GET /oauth/apps/{app_id} and /oauth/apps/{app_id}/info endpoints for APIv4
* Refactor API version independent oauth endpoints
* Implement DELETE /oauth/apps/{app_id} endpoint for APIv4
* Implement /oauth/apps/{app_id}/regen_secret endpoint for APIv4
* Implement GET /user/{user_id}/oauth/apps/authorized endpoint for APIv4
* Implement POST /oauth/deauthorize endpoint
* implement get channels endpoints and updated drivers and unittests
* removed channel deletion on tear down, removed manage permission on get channels endpoints, and updated utils to add constant channel length
* added constants for user, team and channel length, updated context to use the model functions
* make sure team name length should be less than the minimum length and revert underscore to team name validity
* changed post test condition from notfound to unauthorized
* added get user by username endpoint
* added get user by username unit test and driver
* changed username length to 22 characters max
* changed Params to UserName to Username
* reorganized get user by username and get user by email formatting in model/client4
* added get user by email endpoint for APIv4
* added get user by email endpoint unit test and driver
* removed the appended return of user ids on logout
* Added RequireEmail to validate user email. Also updated the get user by email endpoint and unit test
