Export Runtime from PyScript Module (#868)

* export 'pyscript' JS module with runtime attribute, to allow accessing (Pyodide) runtime and globals from JS.
* add docs to explain the js module
* add integration tests for the js module

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

pyscriptjs/rollup.config.js

@@ -27,7 +27,7 @@ export default {
     sourcemap: true,
     format: "iife",
     inlineDynamicImports: true,
-    name: "app",
+    name: "pyscript",
     file: "build/pyscript.js",
     },
     {