PUT to update for experiments should not use actions in payload

[bhufmann]

PUT for experiments command should not use actions in payload (see below). To add or remove traces provide a list of traces UUIDs in the payload and the server needs to validate whether traces need to be added or removed from the experiment by comparing the lists of traces on the server and in the command

[bhufmann]

related discussion: eclipse-cdt-cloud/theia-trace-extension#608

[bhufmann]

Way forward is defined in this ADR: eclipse-cdt-cloud/theia-trace-extension#688

[bhufmann]

#96 proposes a different way to provide actions to the TSP. Adding/removing traces or renaming should be done in a similar way. These actions changing the resource in a way that a new resource is created:

POST /tsp/api/experiments/{expUUID}:add
POST /tsp/api/experiments/{expUUID}:remove
POST /tsp/api/experiments/{expUUID}:rename

Note that ADR eclipse-cdt-cloud/theia-trace-extension#688 needs to be updated for that.