add ordering for icons in tray

[MrFantOlas]

Closes #1489.

The wiki has been update to match the newly available behavior.
This also includes removing previous tray objects that where still held in memory.

[JakeStanger]

Thanks for this. It looks like the IDs are stable/predictable enough I'm happy with this approach, although my only concern is how these can be obtained.

If they can't be easily queried already, we'll need to build in ironvar support into the tray client so these can be pulled out over IPC.

[MrFantOlas]

Apart from looking into the debug logs, I do not of any other way. That said, guess work is probably the most effective way as they all contain their names within the id (hence also the match for containing). For example although the id for discord is not discord because it is contained putting the name of the app is very good guess. It has worked for me in the 10 ish apps I have tested.

[JakeStanger]

Okay I'm not a fan of putting it down to guesswork, even if it's obvious in most cases. I think I want to see a way of querying the IDs before I merge this in, and probably follow up by documenting some common programs.

Happy to pick that work up myself in the next couple of weeks unless you want to.

[MrFantOlas]

As you wish I do not mind adding a commit to this PR.

[JakeStanger]

Cool, appreciate it. If you want to have a look at implementing ironvar::Namespace for the tray client I think that'd be the best way. Not really sure how easy that'll be so if it gets too bad let me know.

[MrFantOlas]

I think this looks ok. Let me know !