Add file storage info to azure_rm_storageaccount_info

The primary and secondary endpoints return blob, queue, and table, but not file. It is easy for me to determine programatically since I can just swap one word in the url but it would be better if that was just reported.

Relevant section of the code: https://github.com/Azure/azure_preview_modules/blob/2413dafa6f979a2070843b073830901cc1b1d868/library/azure_rm_storageaccount_info.py#L482