Dispose experiment/trace back-end resources when closing an experiment from the UI

The TSP allows to open traces and experiments on the server back-end. However, there is now dedicated request available to dispose the back-end resources related to experiments and traces in the back-end. There should be a TSP request to trigger the disposal of resources in the back-end when the front-end close the experiment.

Consider the following API:
`PUT /experiments/{expUUID}:close`

Consider other alternatives before implement this API.

Start by tracing the existing UI flow for closing an experiment and the TSP request definitions used for experiment and trace resources. Compare the proposed PUT /experiments/{expUUID}:close endpoint with existing disposal mechanisms and document the chosen alternative. Done means closing an experiment reliably disposes its back-end resources, with tests covering the request and lifecycle.

Written by the indexing model from the issue text.