Updated Polyscript with its workers feature (#2104)

* Updated Polyscript with its workers feature
* Worked around the inconsistent behavior between Pyodide and MicroPython
* Fixed Pyodide greedy access to undesired Proxy fields

pyscript.core/test/workers/test.py

@@ -0,0 +1,19 @@
+from pyscript import document, workers
+
+
+async def test(interpreter):
+    # accessed as item
+    named = await workers.micropython_version
+
+    version = await named.micropython_version()
+    document.body.append(version)
+    document.body.append(document.createElement("hr"))
+
+    # accessed as attribute
+    named = await workers["pyodide_version"]
+
+    version = await named.pyodide_version()
+    document.body.append(version)
+    document.body.append(document.createElement("hr"))
+
+    document.documentElement.classList.add(interpreter)