hardcoded path for tokenstore.json

[g-clef]

The auth client appears to have a hardcoded path for the tokenstore.json file (

wme-sdk-python/modules/auth/auth_client.py

Line 36 in 62f5a25

self.token_store_file = "tokenstore.json"

). This will cause problems if the client is run in an environment where the system does not have write access to the local filesystem (docker container, for example). I would like this to take an optional argument to either a user-specified file path or a python tempfile.