Create CroogoModelValidator to gather common validation rules - refs #357
Extract Blocks model validation logic into validator - refs #357
Extract Comment Validation logic into model validator - refs #357
Extract Contacts Models Validation logic into validators - refs #357
Extract Menus models validation logic into validators - refs #357
Extracted Node validation logic into Validator - refs #357
Extract Settings models validation logic into validators - refs #357
Extract Taxonomy models validation logic into validators - refs #357
Extracting Users models validation logic into validator - refs #357