Catch all exceptions

- We can actually catch _all_ exceptions at this point, not just
  specific exception types. When passed to an `ApiProblem` constructor,
  the constructor will decide if it implements
  `ProblemExceptionInterface`, and, if so, populate the instance
  appropriately.

  Not catching all exceptions could lead to other errors, and it's best
  to be consistent in error handling in APIs.
Merge branch 'hotfix/exceptions'

Ensure all exceptions are caught.