Add context to exception handler #2236

Same context as renderers which include: the view, args, kwargs, and request. This provides enough contextual information to the exception handlers to handle errors better. In a use case like #1671, a custom handler would allow Sentry to log the request properly.

Things to discuss: Would changing the signature by adding the optional `context` be a problem to users with already existing custom exception handlers? Is it confusing to use `get_renderer_context()` in there? It provides exactly what we need already, so preferred using that instead of "duplicating".
We'll need branching here to handle both the new and the old case, and have the old case in pending deprecation.
You should find some examples of that in older versions - search for `inspect.getargspec` in 2.1/2.2/2.3 or something.