Provide extensions for F#

[KubaZ2]

Description

Here is how you would currently write a minimal API style bot in F#:

let builder = Host.CreateApplicationBuilder()

builder.Services
    .AddApplicationCommands()
    .AddDiscordGateway() |> ignore

let host = builder.Build()

host.AddSlashCommand("ping", "Ping!", Func<string>(fun() -> "Pong"))
    .UseGatewayEventHandlers() |> ignore

host.Run()

Currently, Func<string>(...) is needed for minimal API commands. To improve the experience, it would be needed to provide generic overloads with FSharpFunc<...>. This issue would also be resolved by fsharp/fslang-suggestions#1131.

Of course extensions for services themselves would also be added.

I am also probably unaware of other places in which extensions for F# would be needed. Feel free to suggest them.

The package naming would be {PackageName}.FSharp, so for example it would be NetCord.Hosting.FSharp for NetCord.Hosting.

I think it would be better to write the extensions in F#, as only F# methods can be inlined and optimized by the compiler.