REANA-Commons 0.5.0

• Centralises log level and log format configuration.
• Adds new utility to inspect the disk usage on a given workspace.
  (get_workspace_disk_usage)
• Introduces the module to share Celery tasks accross REANA
  components. (tasks.py)
• Introduces common Celery task to determine whether REANA can
  execute new workflows depending on a set of conditions
  such as running job count. (reana_ready, check_predefined_conditions,
  check_running_job_count)
• Allows the AMQP consumer to be configurable with multiple queues.
• Introduces new queue for workflow submission. (workflow-submission)
• Introduces new publisher for workflow submissions.
  (WorkflowSubmissionPublisher)
• Centralises Kubernetes API client configuration and initialisation.
• Adds Kubernetes specific configuration for CVMFS volumes as utils.
• Introduces a new method, copy_openapi_specs, to automatically move
  validated OpenAPI specifications from components to REANA Commons
  openapi_specifications directory.
• Centralises interactive session types.
• Introduces central REANA errors through the errors.py module.
• Skips SSL verification for all HTTPS requests performed with the
  BaseAPIClient.