Import PyScript Version into Python Runtime (#958)

* Import current version as PyScript.__version__ and PyScript.version_info

* Add integration, python unit tests
 
* Mock pyscript.py with __mocks__/pyscript.js to make jest tests happy

pyscriptjs/__mocks__/_pyscript.js

@@ -0,0 +1,14 @@
+/**
+ * this file mocks the `src/python/pyscript.py` file
+ * since importing of `.py` files isn't usually supported
+ * inside JS/TS files.
+ *
+ * It sets the value of whatever is imported from
+ * `src/python/pyscript.py` the contents of that file
+ *
+ * This is needed since the imported object is further
+ * passed to a function which only accepts a string.
+ */
+
+const fs = require('fs');
+module.exports = fs.readFileSync('./src/python/pyscript.py', 'utf8');