global using (open) - similar to C#10

# Global using (open)

I propose we add a capability to have a similar functionality of [global using in C#](https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-10#global-using-directives), so we can put all open statements in a single file at the top of the project

```csharp
//GlobalUsings.cs
global using Newtonsoft.Json;
global using ..... ;
....
```

maybe in F# could look like

```fsharp
//GlobalOpen.fs
global open Newtonsoft.Json
global open ....
...
```

i have tried the 'AutoOpen" attribute trick on the top of a single file module on top of my project files, but doesnt work unfortunately, the other files/modules still cannot see the already opened namespaces

maybe AutoOpen could be declared on namespaces too as a possible alternative?

## Pros and Cons

The advantages of making this adjustment to F# are much less code:
**more succint --> F# is succint but here C# is more succint atm** , so maybe that could be ported.

``F# is a Succint, Robust and Performant language``

The disadvantages of making this adjustment to F# are .. ? dont know if there is any

## Extra information

Estimated cost (XS, S, M, L, XL, XXL): S? don't know

## Affidavit (please submit!)

Please tick this by placing a cross in the box:
* [X] This is not a question (e.g. like one you might ask on [stackoverflow](http://stackoverflow.com)) and I have searched stackoverflow for discussions of this issue
* [X] I have [searched both open and closed suggestions on this site](http://github.com/fsharp/fslang-suggestions/issues) and believe this is not a duplicate
* [X] This is not something which has obviously "already been decided" in previous versions of F#. If you're questioning a fundamental design decision that has obviously already been taken (e.g. "Make F# untyped") then please don't submit it.

Please tick all that apply:
* [ ] It is not a breaking change to the F# language design : i supposed it wouldn't be breaking, as a single file at the top maybe still keeps the dependency ordering for open statements before anything else in the .fsproj - please note in the comments below remarks related to possible issues with shadowing and in general the "explicit lang design" of F#.
* [ ] I or my company would be willing to help implement and/or test this

## For Readers

If you would like to see this issue implemented, please click the :+1: emoji on this issue. These counts are used to generally order the suggestions by engagement.

Start by reading the proposal and its C# global using and F# global open examples. No implementation files, tests, or entry points are named, and the issue leaves the syntax, ordering, shadowing rules, and AutoOpen alternative unresolved. Done would require an agreed language design and an implementation and test plan.

Written by the indexing model from the issue text.