Added warp-tls integration

Decided to forego the Web.Scotty.TLS route since importing scottyApp from Web.Scotty would have caused a circular import. Just included scottyTLS in Web.Scotty.

```haskell
{-# LANGUAGE OverloadedStrings #-}

import           Web.Scotty

main :: IO ()
main = scottyTLS 3000 "server.key" "server.crt" $ get "/" $ html "ok"
```