Add ExtendsOr, ExtendsAnd, and ExtendsThenElse types

[tmillr]

A few basic utility types that act as || and && shorthands.

The third type is simply an if/then/else conditional which simply mirrors the behavior of typescript's extends ternary conditional expression (yeah I know not very useful but it allows for alternative syntax/style).

These utilities could also have other names such as:
ExtendsOr -> Or
ExtendsAnd -> And
ExtendsThenElse -> Cond or Condition or Conditional or Ternary etc.
...but I thought these names were ok.

These are all simple utilities, so how they work should be rather easy to figure out, although I did try to provide some examples (including an example that reflects a problem that originally inspired this idea having to do with Parameters<> erroring if it is not sure that it is receiving a Function).

[sindresorhus]

@Tyler1205 If you have time, it would be great if you could help review some of the other open pull requests. 🙏

[sindresorhus]

I'm a little bit conflicted about this. It tries to simplify code with utilities, but we also have to learn the utilities. When I person reading the code sees ExtendsOr, they need to look it up, but when using extends directly, they don't need to do that.

[papb]

I am not sure either. I have also needed these helpers in the past in a few situations, but I just defined them myself so anyone reading my code will be able to understand without having to look it up.

[sindresorhus]

I have decided to decline this as the benefits are not worth the learnability overhead.