Add a way to add middleware to the start of the chain.

[MatthewPopat]

If you create a RestClient that uses axios middleware as the last step in the chain then applying more middleware to that client would be pointless. It would be nice to be able to add middleware ad hoc to the start of the chain. Maybe the best solution to this would be to reverse the order that middleware is applied so that the first one you use() is the last one that is called.