Support stacktraces

[Former user]

https://docs.sentry.io/development/sdk-dev/interfaces/exception/ http://hackage.haskell.org/package/base/docs/GHC-ExecutionStack.html

I'm not entirely sure it's possible to retrieve the stack in Warp.setOnException, but it's something to verify before adding the support to also a attach a stacktrace to the exception.

[dp wiz]

I've checked the docs and haven't found an obvious way to extract stack trace from SomeException type. And for traces to work application handlers should be greased with HasCallStack everywhere interesting.