[Feature Request]: Support Python operators on Python.Value

[jabraham17]

Currently, the way to call Python operators from Chapel is to explicitly call the dunder method

use Python;
var interp = new Interpreter();
var pyInt1 = interp.toPython(10);
var pyInt2 = interp.toPython(11);

var res = pyInt1.call("__add__", pyInt2);

While this is a simple/silly example with plain integers, many libraries overload these dunder methods in interesting ways to create their user interfaces. Translitering these libraries in Chapel-Python interop can be awkward because of these dunder method calls.

However, we could support many of these Python operators as Chapel operators. For example

operator +(lhs: owned Value, rhs: owned Value) {
  return lhs.call("__add__", rhs);
}

I think we should support as many of these dunder methods as we can