Upgrade to Orchard 1.8

The changes I made to the module are the following:

- Changed to the project's target framework to .NET 4.5. This is needed for the module to compile with Orchard 1.8.
- The project Web.config and the Web.config files under the Scripts and Styles folders are updated accordingly.
- Reflecting to these changes, the Views/Web.config file is removed, as it's no longer needed.
- Empty folders are deleted (Models, Views, Controllers).
- Removed the image with the AngularJS logo, as it's unnecessary for the module.
- Removed the packages.config file, since the static resources have to be in the Scripts/Styles folder, so the NuGet package is unnecessary, because they have to be updated manually.
- Moved the "angular-csp.css" file to the Styles folder.