Azure integration

• fixes broken conda shell command

• adds methods to access Azure Storage - work in progress!

• adds methods to access Azure Storage

• further programming

• ignores virtualenv directory

• adds exception for Azure file/blob operations

• makes minor changes to private methods

• fixes typo

• changes version of conda from which on to use "conda activate" - see https://docs.conda.io/projects/conda/en/latest/release-notes.html?highlight=release%20notes#id105

• fixes indentation error

• corrects method name

• adds required helper functions for parsing file paths to container/blob names

• amends earlier commit

• adds missing modules

• fixes variable names

• assigns correct Azure account object to RemoteProvider class

This is an attempt at adding Azure Blob Storage as a RemoteProvider/RemoteObject to snakemake. The major prerequisite would be installation of the azure metapackage, which is currently only well distributed through PyPI.