Porting variable-length-quantity

I'm opening this issue to see if there are any existing efforts to port [variable-length-quantity](https://github.com/exercism/problem-specifications/blob/main/exercises/variable-length-quantity/description.md) to Haskell. If not I'm happy to take this on myself - so far I haven't seen any Haskell exercise that calls for bit manipulations so this also provides some extra aspects of the language.