Remove all references to "email" since we don't actually store the email any more, only the opcode. We were duplicating the opcode as the email recently, might as well remove it to avoid confusion
- remove the methods to return the server tokens, we currently use the opcode as the token directly
- raise errors if we try to set the opcode through the plugin since we are doing so directly from the javascript in the KVStore
This is part of the workaround for
e-mission/e-mission-docs#930