[SUGGESTION]: Package-level fields

Module-level fields have been introduced since Haxe 4.2.0 to open the possibilities of procedural programming in Haxe (according to https://haxe.org/blog/module-level-fields/)

since this is an option, I believe it'd made sense to open the possibilities of package-level functions like ActionScript had in some instances like `flash.media.scanHardware` or `flash.system.fscommand`.

My suggestion would be to allow (maybe for the first time ever) a lower-case .hx file called `package.hx` or the name of the package itself (i.e. `audio.hx` in `system.audio`), which would be another way to implement classes in a single file module but be spread within the package.

Example:

```hx
package dot.addons;
//in package.hx
class Foo
{
public static function myFunc()
{
trace("calling from Foo");
}
}
class Bar
{
public static function myFunc()
{
trace("calling from Bar");
}
}
```

```hx
// Main.hx

import dot.addons.Foo;
import dot.addons.Bar;

function main()
{
Foo.myFunc();
Bar.myFunc();
}
```

and, with the insertion of module-level fields, you could now do this:
```hx
// in package.hx
package dot.addons;

function analyzeParams()
{
// code block...
}
```

```hx
// Main.hx

import dot.addons.analyzeParams;

function main()
{
analyzeParams();
}
```

this would be proper for stb single files that are not necessary for them to be within a class in Haxe.