azurebatch config doesn't expose tokenDuration parameter, causing sadness

[tanaes]

I recently discovered the existence of the azure.storage.tokenDuration parameter in the wrong way -- that is, by having a large and expensive workflow fail spectacularly 2/3 of way through compute due to token expiration. 🙃 The nature of this failure appears to be a particular bummer, as it seems to have interfered with cacheing, requiring me to bodge together a fix to prevent needless re-execution of most of the expensive steps.

I'd propose exposing this parameter in the configuration file!