Create epic for eScienceGateway / workflowhub knowledge graph

[OliverWoolland]

• [x] #8
• [x] #9
• [x] #10
• [x] #11
• [x] #12
• [x] #13
• [x] #14
• [ ] #15

[stain]

To be discussed in EuroScienceGateway meeting 2024-05-03 -- several of these can done by other ESG contributors.