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".
A `PendingDeprecationWarning` might be a good idea yea. @tomchristie thoughts? Any suggestions to what the message should read?

"`exception_handler(exc)` is pending deprecation. Use `exception_handler(exc, context)` instead.",