Add redirect to flask-babel pythonhosted documentation

[TkTech]

In the same nature as #203, the flask-babel documentation has moved to https://flask-babel.tkte.ch. However, the old, out of date documentation is still on pythonhosted as the #1 search result, and there are many existing links pointing to it. We used to be able to upload an index.html with a redirect, but this appears to be gone and all we can now do is destroy it.

Flask-Babel issue at python-babel/flask-babel#176.

[TkTech]

Apologies for the incorrect issue label.

[TkTech]

Is this still possible @ewdurbin?

[ewdurbin]

Yes it is.

@TkTech should the URL be preserved on redirect?

[TkTech]

Awesome! Nope, just the root, since the structure will likely change.

[ewdurbin]

redirect is configured