Adding the notion of scan sequences to the redis data structure
Following demand by @meyer and @sole there is a need to be able to group scans in sequences.
There is a proposal by @sole : https://gitlab.esrf.fr/sole/data_policy/blob/master/ESRF_Scans_and_Sequences.rst
The first TODOs are:
- add a container in the redis tree as parent of scan
- add entry in SCAN_SAVING
- if needed create a specific container type to allow filtering
- establish the logic how this container is supposed to be used