Rethink deprecation of addError / addWarning and maybe even add addInfo and default implement those

[laeubi]

I find addWarning / addError/ ... much more descriptive and easier to read/understand than lengthy multi parameter methods.

Together with java capability of default implemented interface methods, I think we should even add more such useful methods as default implemented to the interface, e.g. ones that don't require a Throwable

[laeubi]

Maybe it would even be better to have a dedicated MessageContext API, users of that API can then just inject whatever is required ...