Fix DisplaySolution::fillMessage() drops info and execution_info from SubTrajectory messages

[lunarifish]

When clicking the "Execute solution" button on the Motion Planning Tasks panel, the action goal sent to the execute_task_solution action server was missing the SolutionInfo and TrajectoryExecutionInfo fields in every SubTrajectory.

The internal DisplaySolution::Data struct had no info_ or execution_info_ fields. Consequently, DisplaySolutionfillMessage() had nothing to write back for SubTrajectory::info and SubTrajectory::execution_info, so they were always sent as empty values.

Any action server that relies on execution_info.controller_names or other SolutionInfo fields like markers, planner_id, cost, id would receive empty data. I happened to hit this because my action server uses execution_info, and I triggered it through the panel button.

[rhaschke]

I deliberately chose to drop the SolutionInfo to reduce the memory footprint.
However, I agree to store the ExecutionInfo as this is obviously required for execution.
All other fields (like markers) are not required for solution execution.

[lunarifish]

Okay! I have removed SolutionInfo from the Data struct.