Created and implemented TemplateNotFoundException. It is thrown when a template is not found or is not readable
Created base of first widget: PageWidget

This widget will help us to evolve Cyborg CMS. Because it has a
lot of features that we need to improve/implement, like:
* Database connection
* ORM
* Composer
* Parameters and requirements on routes
* Define how to install a widget
* Layout bootstrap
* and others...