Relation tables

this adds two relation tables and deploys them during db setup.

• the relation_role (RR) [1] table defines possible relations
• the related_datastream (RD) [2] table holds datastreams that are related to an other datastreams and the type of realation (reference to realtion_role)

The RR is (currently) prefilled with just a single value (see [1]), which defines a derived product and is not intended to be filled at other than initially. IOW it serves static data.

The RD table is filled by the QAQC workers, which identifies un-related datastreams as raw and related ones as data-products. In the example below [2], the first row read as: "datastream 1 was created by datastream 2". So the datastreams 1 and 3 are data-products because they appear in the table on the left side of the relation created_by. On the other hand, the datastreams 2 and 4 are interpreted as raw streams as every other datastream would, that is not listed at all (e.g. 5, 6 or 21).

I tried to implement the tables as close as possible to the (still discussed) version STA-2.0 Relation extension.

@david.schaefer: FYI

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[1]

[2]