feature/datagrid

Moved rendering to decorators. Replaced sinon fake-server with api-mocker

To install api-mocker
sudo npm install -g apimocker

To start mock server (needed for the demos)
apimocker --config apimocker_config.json

- [x] finish the code
- [x] gather feedback for my changes

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   | none
| Fixed tickets | none
| Doc           | none