Add twining technique to replacement_sdts in Control Snapshots

[Barbara Schlottfeldt]

Could be an option for the value in replacement_sdts to take the closest active snapshot existent in the table, so if a snapshot is not active the replacement_sdts will take the timestamp value from the closest active one.
Idea came from @marcfinger and its based on the technique shown here:
https://www.linkedin.com/pulse/lets-twine-again-lars-r%C3%B6nnb%C3%A4ck/