Authentication process

[tadam313]

The current process is very tedious. Especially when a token expires need to manually reissue the request with the newly fetched token which is delegated to the user. This results in many manual preparatory/integration work before someone can start using this package. The amount of LOC spent on integrating this package should be dramatically reduced.

If the current process can not be improved anyhow, need to provide built-in authentication solutions (e.g separate auth namespace) to mitigate this problem.

Keeping authentication detached seemed a reasonable way, but it should not degrade the ease of integration.