azureblob: delete archive tier blobs before update if --azureblob-archive-tier-delete
azureblob: delete archive tier blobs before update if --azureblob-archive-tier-delete

Before this change, attempting to update an archive tier blob failed
with a 409 error message:

    409 This operation is not permitted on an archived blob.

This change detects if we are overwriting a blob and either generates
the error (if `--azureblob-archive-tier-delete` is not set):

    can't update archive tier blob without --azureblob-archive-tier-delete

Or deletes the blob first before uploading it again (if
`--azureblob-archive-tier-delete` is set).

Fixes #4819

ncw/rclone,ncw/rclone,ncw/rclone,ncw/rclone