Remove Py.python and Py.expr_python

[MangelMaxime]

Description

There are emitStatement and emitExpr which cover the same feature with the bonus of accepting argument so the user can use $0, $1, etc. to access them in the expression.

[dbrattli]

I don't think emitStatement does the same thing as python. The python one supports string interpolation to handle arguments e.g:

let add a b = Py.python $"""
    return {a+b}
    """

This produces:

def add(a: int, b: int) -> Any:
    
    return (a + b)

[dbrattli]

The JS equivalent was not removed so I think we should add this back: https://github.com/fable-compiler/Fable/blob/main/src/Fable.Core/Fable.Core.JS.fs#L547

Better naming would be nice, but there are some magic happening to get syntax highlighting in vscode for the contained code https://github.com/alfonsogarciacaro/vscode-template-fsharp-highlight