Create a pipeline sample using Cloud Functions

[deflaux]

Write a cloud function that monitors for new objects added to a particular bucket and calls the pipelines API to run a pipeline on that file.

For example, when a new BAM file is added to the monitored bucket, the cloud function can call this pipeline to create the BAM index for the file.

For more detail, see https://cloud.google.com/functions/docs and https://cloud.google.com/functions/calling#google_cloud_storage