ErrorPage: L10n
WebPageImpl: When displaying a stack trace, also display the type of the exception
- I'll probably move the function to ErrorPage in a following commit
- L10n doesn't make sense here, Exceptions are English anyway.
Deprecate WebPageImpl.addErorBox() and use ErrorPage instead whereever trivially possible:
- For the non-trivial cases, explain in a TODO what needs to be changed so we can use ErrorPage
- Notice that we are safe to remove the Logger.error() calls because ErrorPage does that for us.