Missing tools in workflows are difficult to replace due to no connections

[hexylena]

If you have a workflow you upload with missing tools, you can occasionally replace these missing tools with something else that's already present on the server.

But it's extremely hard to tell how they should be connected, all of the outgoing connections from missing tools are gone (or not rendered xref #2942), so you have to check the JSON in order to figure out where the outputs should go.

If we could just show the connections going to their outputs it would be extremely helpful. If we could show the outputs + their internal labels it would maybe be even more helpful.

cc @shiltemann

[mvdbeek]

This and inputs/outputs that disappeared due to version changes.

[mvdbeek]

and inputs/outputs that disappeared due to version changes.

that part is fixed, and showing connections for tools that are not there anymore at all should be trivial to fix at this point.