Upload logs to Azure Storage

Before using this role, create a storage account in Azure and obtain
an `Access key` for the account.  You may create a container within
the account, or allow this role to create the container (or
containers) for you.

**Role Variables**

.. zuul:rolevar:: zuul_site_upload_logs
   :default: true

   Controls when logs are uploaded. true, the default, means always
   upload logs. false means never upload logs. 'failure' means to only
   upload logs when the job has failed.

   .. note:: Intended to be set by admins via site-variables.

.. zuul:rolevar:: zuul_log_partition
   :default: false

   If set to true, then the first component of the log path will be
   removed from the object name and added to the container name, so
   that logs for different changes are distributed across a large
   number of containers.

.. zuul:rolevar:: zuul_log_container

   If partitioning is not enabled, this is the name of the container
   which will be used.  If partitioning is enabled, then this will be
   used as the prefix for the container name which will be separated
   from the partition name by an underscore.  For example, "logs_42"
   would be the container name for partition 42.

.. zuul:rolevar:: zuul_log_container_public
   :default: true

   If the container is created, should it be created with global read
   ACLs.  If the container already exists, it will not be modified.

.. zuul:rolevar:: zuul_log_path
   :default: Generated by the role `set-zuul-log-path-fact`

   Prepend this path to the object names when uploading.

.. zuul:rolevar:: zuul_log_create_indexes
   :default: true

   Whether to create `index.html` files with directory indexes.

.. zuul:rolevar:: zuul_log_path_shard_build
   :default: false

   This var is consumed by set-zuul-log-path-fact which
   upload-logs-azure calls into. If you set this you will get log
   paths prefixed with the first three characters of the build
   uuid. This will improve log file sharding.

   More details can be found at
   :zuul:rolevar:`set-zuul-log-path-fact.zuul_log_path_shard_build`.

.. zuul:rolevar:: zuul_log_connection_string

   The Access key connection string for the Azure storage account.