Implement method that reads vendor libs from core.json

* includes them at the beginning of initTemplate()

If this fails it will put an error message into log, but will continue loading (which result in a broken web UI)

@PVince81 I guess this was your idea ;)

@DeepDiver1975 @LukasReschke 
Well, they are not the worst thing on earth. And at least you know directly what has gone wrong. ;-)