CORPORATION: Add new API to check if player can create corporation

[catloversg]

As we discussed at #1587 (comment), this PR adds that API.

[d0sboots]

Optional: Right as I started reviewing this, I was thinking it might be better to expose (programmatically) why you can't create a corp. Now I see you've gone and made a nice enum for handling it internally. What do you think? True/false is a much simpler API, so I'm sort of on the fence.

If you went that route, you'd want to expose the enum, which would lock us in on these strings.

[catloversg]

Returning an enum instead of true/false is a good idea. I'm all for it. However, I also have the same concern about "string-messages-in-enum-API". That downside looks too big to me.

[d0sboots]

What if we made the enum just symbolic constants/names, and kept the string messages internal to the one place that needs them (logging)?

Edit: Just throwing ideas out here, ultimately I'd be OK with true/false, but since we've seen how hard it is to correct APIs IMO it's worth extra think time when adding them.

[catloversg]

What do you mean by "symbolic constants/names"? For an enum, we need it to be in this form:

export enum TestEnum1 {
  One = "string 1",
  Two = "string 2",
}

We cannot use it like these ones:

export enum TestEnum2 {
  One,
  Two,
}

export enum TestEnum3 {
  One = 1,
  Two = 2,
}

EnumHelper.ts will throw a fit at that.

[d0sboots]

I was thinking like

export enum CorporationCheckResult {
  Success = "Success",
  NoSf3OrDisabled = "NoSf3OrDisabled",
  CorporationExists = "CorporationExists",
  UseSeedMoneyOutsideBN3 = "UseSeedMoneyOutsideBN3",
  DisabledBySoftCap = "DisabledBySoftCap",
}

I.e. the enum values are just restating the names. The values aren't any more useful than the keys here, the point is that it fits the rest of the enum architecture and we aren't worried about value stability.

[catloversg]

I tried to implement it in the latest commit.

[catloversg]

@Snarling We are doing an unusual thing in the API here (return an enum instead of true/false), so I want to hear your opinion.