Add --location-policy flag to s3-to-dc

[omad]

At the moment, s3-to-dc provides an almost complete alternative to datacube dataset add and datacube dataset update, as well as including extra features like indexing from STAC and glob based indexing from S3 buckets.

However, it doesn't allow updating the location of an already stored dataset, like can be done using datacube dataset update --location-policy archive|forget documented in datacube-core.

This feature would be used frequently in the DEA product release process when promoting products from Development to Production.