Allows setting fixed special scoped parameters for start locations

[Procyonae]

Summary

None

Purpose of change

Closes #72479
Needed for #72561 and #72809

Describe the solution

You can set singular or multiple parameters to singular values which then override those calculated normally when the mapdata is initialised, so you don't have to set every parameter.
You can also use this to set a parameter to a 0 weight value for it to be start location only.

set_parameters somewhat cargo cults overmap_ui's set_special_args used for debug setting parameters

Describe alternatives you've considered

The bool being stored in overmap_buffer is pretty gross but I couldn't see how to easily scope it otherwise

It still calcs the overridden parameters which is suboptimal but I didn't fancy attacking the function that spits them all out together

If I or someone else gets around to doing #72529 the functions will probably want moving to overmap_special but I didn't fancy trying to scope that for this

Testing

Tested with #72561

Additional context

[Maleclypse]

As an in repo use case of this You can also use this to set a parameter to a 0 weight value for it to be start location only. can you have the Ready or Not Mansion start with special ferals only exist in that start?

Sorry to request some extra work from you but I think that will both demonstrate a usecase and close a stable blocker.

[Procyonae]

As an in repo use case of this You can also use this to set a parameter to a 0 weight value for it to be start location only. can you have the Ready or Not Mansion start with special ferals only exist in that start?

Sorry to request some extra work from you but I think that will both demonstrate a usecase and close a stable blocker.

Backporting this for that purpose doesn't seem like the best solution bc it would require a pretty hefty parameterisation of mansion_boarded into the normal mansions (likely several 1000 line changes)
Instead I'm doing an PR that places all the special ferals with a start eoc expanding on the existing one, removing them from normal spawns.

Thanks for pointing out the mansion start though, I'll still do the parameterisation at some point down the road to cut down on repeated maps and make future adjustments easier as well as adding variety by allowing the start in all the different mansion layouts but I don't want to do that rn (I also want to give the mansions driveways and parking at some point)

[Procyonae]

Opened the mansion feral PR #72695

[Procyonae]

As an in repo use case of this You can also use this to set a parameter to a 0 weight value for it to be start location only. can you have the Ready or Not Mansion start with special ferals only exist in that start?

Sorry to request some extra work from you but I think that will both demonstrate a usecase and close a stable blocker.

Is there any issue with using a draft PR as a use case? I'd of put this in with the evac centre PR but I thought it made more sense to separate them