Add option for exception catching in wasm

- Adds `VTK_WEBASSEMBLY_EXCEPTIONS` cmake setting to
    enable exceptions at compile+link time with `-fexceptions`.
- This setting will allow the C++ unit tests to print additional stack traces
    when an uncaught exception is thrown, at the expense of greater binary size and slower execution.
- The `ENABLE_EXCEPTION_CATCHING` option requires a list of functions from which exceptions may be thrown.
    This commit allows all functions to throw exception catching with `DISABLE_EXCEPTION_CATCHING=0`
    as we cannot know all possible functions that could throw exceptions.