Transfer account from official server

Its possible to transfer the current pokemon go account from the official server, by dumping all responses during the authentication phase. Maybe outsource this feature into a library, which generates some kind of save file. Then during the very first connect on a custom server, the progress from the official servers could get imported.

No files, tests, or entry points are named. Start by locating the authentication flow and how responses are handled; clarify the save-file format and import behavior before implementation, then verify that an account's official-server progress can be imported on its first connection to the custom server.

Written by the indexing model from the issue text.