Improve the error and exception handling
The new errorhandling in TYPO3 is way too unflexible.
- Errors are "converted" to exceptions. This is not very useful because every php warning will be turned into an exception. and will stop the script execution.
- DIsplayed error break the backend layout and make forms unusable
- Errors and exceptions are only displayed, but there's no build-in possibility to write errors and exception to a log.
- introduce a new parameter for errors which should be handled by the error handler. The already existing parameter "exceptionalErrors" is used only for the error which should throw exceptions.
- Display the errors as flashmessages in the BE and as TsLog messages in FE (in the adminpanel)
- implement logging of errors and exceptions to the different logging systems TYPO3
(issue imported from #M12093)