Move the markup sanitization logic to its own component

[stasm]

We could simplify <Localized> and separate concerns nicely by moving the markup sanitization logic out of it into a new component.

[stasm]

I have a WIP PR in #211 which works, but unfortunately Enzyme doesn't like this change for some reason and all tests fail. I expected wrapper.contains to just work but I was wrong. Any help will be appreciated.