UK: increase version length to 255, closes #701
PLD: test and catch owner validation errors
PLD: assign owner var correctly
DW: Added test to recreate the issue
DW: All the users can remove themselves from a project. Test includede
UK/RR: fix PUT update on user profile endpoint
Merge pull request #707 from onaio/700_all_user_should_be_able_to_remove_themselve_from_project

700 all user should be able to remove themselve from project
ME: added TempToken model
ME: added migration file for TempToken model
ME: added TempTokenAuthentication class
ME: refactored 'get_temp_token' function
ME: added 'DEFAULT_TEMP_TOKEN_EXPIRY_TIME' in common.py
ME: refactored calculation of expiry date
ME: added 'expire' action to delete token
ME: updated 'TestConnectViewSet' with tests for temporary token
added 'TempTokenAuthentication' to the default auth classes
ME: added documentation for temporary token functionality