Fix DXDataObject.closeAndWait
[PTFM-10293] Fix dx find executions -n > 999
Make cli/exec_io only raise DXCLIError and do so for --input parsing errors
Fix error handling for setting executable in dx add/update stage
Improve dx describe workflow and better error handling

- IO specs displayed when describing by name
- Inaccessible stages rendered as such in describe, list stages
- dx run refuses to run a workflow with inaccessible stages
Changelog and dxR version update for v0.78.1