Optional ints and floats

[FedorLap2006]

Right now we need a better way of handling min max constraints and their zero values.
As @iopred and @CarsonHoffman suggested, we should use *int and *float64, but I think I've found a better way of doing that.
While still holding on to the idea of using pointers we can create utility functions (which will be also useful in #1026 and #1052) for constructing an optional int and an optional float. They would look something like that:

func NewOptionalInt(v int) *int {
     return &v
}

What do you think?

[danbrakeley]

This a lot of precedence for this, for example here's what the AWS Go SDK uses: https://github.com/aws/smithy-go/blob/main/ptr/to_ptr.go

You could probably shorten the name from NewOptionalInt to just Int as well, or put it in a package called ptr like the AWS example, so the user can type something short and simple, like ptr.Int(n) (compare this to discordgo.NewOptionalInt(n)).

[FedorLap2006]

I mean yeah, but we shouldn't embed everything in discordgo, it was just a utility function, but making a package, I don't really know. Probably would be better just to leave it as it is, being a pointer, and remove the functions.