[enhancement] Detect blob-name collisions in sinks

[mkeskells]

When a sink uploads a file, there is a chance that the blobnames will collide
In that case (currently) the blob is overwritten with a new blob

I suggest that thiis behavior should be enhanced to allow the result to be determined by a policy

this could occur because of the resuart of a task, trecovery from timeout etc where the content is the same, or other situations where the content has changed

e.g.

• OVERWRITE (default, current behaviour) generate a new version
• NEW_NAME - generate a new blob name, and retry
• CHECK_NEW_NAME - check the file content, if it matches then do nothing, otherwise do the same as NEW_FILE

there may be other options - I presume that for the exactly once there may be a CHECK_FAIL - as it muct be the same content

Having CHECK_NEW_NAME would reduce the number of blobs uploaded, the therefore the TCO

Happy to assist with a PR/discuss further if the maintainers consider this is a viable direction