Review and update the Angular Essentials document (Marketing)

[zdrawku]

Angular Essentials document (internal) needs a review. We might want to add/mention some of the new features and updates available with the latest versions. Consider updating the ToC area as well, example would be combining the Components and Directives sections and leaving only the component communication section, as essentially components are falling under the definition of a Directive with a template, Directives are actually structural directives and we have a Attribute directives as a 3rd type.