Link to forign key table (show relation data)

Description of the issue

We provide an interface and view to a relational database. We should make sure to support most of the basic relational data operations such as resolving the tables that are used to link a foreign column to create a foreign key to map to another tables column.

By making this relation obvious, we support users in understanding the data they look at. As the foreign key (FK) show an identifier resolving the data behind it enhances the current context of the data.

Ideas of solution

On a tables view page we show the columns. Columns used as FK should be made visible and relational information can be fetched. How much data we actually need to fetch (full row, only value) is not clear yet. The example is not the best to show that :D

For example this table:
https://openenergyplatform.org/database/tables/biomass_solid_bpchp_heat_low_decentral

The column energy_bus referances the column name of the table bus here:
https://openenergyplatform.org/database/tables/bus

We can also use the OEMetadata to find the information about the relation in the frontend/client this saves a query and enables us to build the correct query for fetching the relational data.

Workflow checklist

• I am aware of the workflow in
  CONTRIBUTING.md