Add endpoint to close experiments

This endpoint can be used to close the experiment and upon reception of the message, the server can dispose can dispose allocated resources. The Trace Compass server will dispose the experiments and close all state system and index files.

Use PUT for this, because sending this message multiple times will have the same outcome. The api should look as follows.

`/tsp/api/experiments/{expUUID}:close`

Use this notation with `:close` as suffix, will allow to create dedicated actions for different behaviours, like deleting trace indexes (e.g. delete supplementary files of Trace Compass server, rename, copy etc)