Improve performance of slow requests

[georgiana-b]

Some requests are taking way longer than they should given their complexity:

• Get node details
• Get edge details
• Get cluster details

---

• Create a cluster
• Update a cluster

While the db may have part of the fault most of the logic in these requests is happening in the code so clearly there is a lot of room for improvement there. It is not obvious what's causing the drag so the requests need to be profiled but just as a pointer:

• most of the logic for the first 3 happens in the serializers (e.g. node details)
• most for the other 2 happens in the cluster writers (create cluster and update cluster)

[georgiana-b]

@mnagy If you start the server and go to /docs you can see all these endpoints prettyfied in Swagger and it's much easier to make requests.

[georgiana-b]

@mnagy Also feel free to assign yourself and move this around in Waffle as you go.

[zufanka]

@mnagy have you been doing something with this?