New state at visualization for nodes and edges to mark them as "done" when double-clicking them

[Ravriely]

Basically the same goal as the PR #165

When double clicking a node, it marks it as done by adding a green outline and transparency
When double clicking an edge, it marks it as done by graying it out and dashed

The states of the nodes and edges are made persistent using stable keys stored in the LocalStorage, unlike PR #165 where the "done" states were wiped out when reloading the page

[Ravriely]

Closes #193

[Ravriely]

Hey @greeny, it's been open for quite a while now, I was wondering if you'd had a look at this PR, that feature would be really useful to a lot of us

[greeny]

Hey, since new Tools are very quickly moving towards official release, I'm not currently accepting any PRs to old tools

[Ravriely]

Thanks for the response, I realise that the new tools are due to be launched very soon (when can we expect them?), but we’ve been using the old tools for several months now, and some quality-of-life improvements to them would have been welcome for some of us :)

[Ahubbart]

Would love to have this added, got plans for some big factories coming up, and this would be a godsend. I know that no more PRs are being accepted, but I would be super grateful if this could also be added in the next patch/update. 😃