Add ability to score text readability

[mlewis-everley]

This is an idea I have had for a little while, I am not entirely sure how it would manifest though.

It would be nice to measure the readability (reading age, complexity of text) as part of this module. I did some digging around and found this library: https://github.com/DaveChild/Text-Statistics

The library covers several standard scoring systems. I guess you could just use the library to return a score (based on the pages content) and then provide some links for users to match that score to relevant age, etc.

Another issue would be how it works with multilingual content. It looks like the text-statistics library is targeted mostly at English, I am not sure how well it would work with other languages. Looking through the issues it may work OK with latin derived languages, but doesn't seem to work with other languages.

Is this something that might be worth considering for this module? Or maybe it is better as a module by itself?