BlueprintParser refactor

@zdne Can you review this branch and merge it with `pksunkara/refactor`? I need this to be done in order to check for global duplicate in `ResourceGroupParser.h`.

Also, please check my questions on the diff below. Thanks.
So we basically need to skip process signature and description of a blueprint section and go directly to processing nested sections – you can either reshape the architecture a bit to allow this directly (e.g. add nested section checks at the beginning) but since the blueprint parser is so special – I would use the same approach you did with parsing metadata  (which is technically a nested section) – check in process signature for a nested section type and if so use `processNestedSection`. What do you think?