Increase documentation

[miguems]

as per @senakafdo suggestion, add documentation about:

• Index.js
• @ove-lib/appbase and the exports provided by it
• Exposing node modules
• Introducing APIs and Swagger extensions for API documentation
• The window.ove.context object and what is stored by default and what can be added into it
• The window.ove.socket object and the on/send methods
• The other elements on the window.ove.state object, load/cache methods and name property.
• The window.ove.layout object and its properties and their usefulness.
• The need for the unselectable class in CSS.
• The lerna build system, package.json etc.