Fix mechanic not being persistent

[zonkmachine]

The 'Breakdown Servicing' character changes face in between chats. This is because Character.New() is called from the onChat function and somehow doing it with a persistent seed doesn't give persistent result. I don't know why that doesn't work. Instead I simplified the code a bit by generating the character on onCreateBB.

[impaktor]

I'm guessing this might be related: #4810

[zonkmachine]

I'm guessing this might be related: #4810

Yes. PR #4817 is mentioned in issue #4810 but it doesn't look done yet.
I'll look into the modules discussed in #4810.

[zonkmachine]

@impaktor I've tested DonateToCranks and GoodsTrader and they are persistent. However, there is an intermittent problem with onCreateBB being rerun on bulletin boards that are already existing, described in #5305, and I think this is what's failing here. It's an intermittent issue so it may take some time to trigger it. At the time of #4810, #5305 would have behaved differently and I haven't seen onCreateBB being triggered on those earlier builds, but I think the core issue would have been the same/same-ish.
Edit: FuelClub also has a working persistency.

[zonkmachine]

This PR is ready for review. For the other/similar issues mentioned above I believe they need more troubleshooting and most, if not all, depend on other issues.

[impaktor]

Looking at the code, doesn't look like it will be persistent, i.e. same mechanic on same station always? I think that was the intention with the old code. Or are you using the local rand = Rand.New(station.seed + seedbump) anywhere?

[zonkmachine]

Thanks!

Right, I don't actually know how to fly around in this game and it looks like I actually have to do that now. Will try it... :)

For the code I guess I have to go:

 local onCreateBB = function (station)
        local rand = Rand.New(station.seed + seedbump)
        local n = rand:Integer(1,#flavours)
-       local mechanic = Character.New()
+       local mechanic = Character.New({seed=rand:Integer()})