Implement more flexible error handling

[jvalkeal]

• Add exception handling around new interface CommandExceptionResolver which allows to define a chain of resolvers to process errors before exception is bubbled up to result handlers.
• Will be foundation to add more sophisticated error handling features compared to what spring itself have for rest layer.
• Resolver returns CommandHandlingResult holder which further can be used to make a choice what to print into console and if spesific exit code should be used in non-interactive mode.
• Exception handling can be defined globally and per command giving a change for user to customise i.e. error thrown by parser.
• CommandParserExceptionResolver replaces CommandParserExceptionsExceptionResultHandler and provides more meaninful message for missing options.
• Fixes More descriptive error message when required option is not present #503