update docs: add screenshots

docs/50_Components/Alert.md

docs/50_Components/Badge.md

docs/50_Components/Button.md

docs/50_Components/Callout.md

docs/50_Components/Card.md

docs/50_Components/Infobox.md

docs/50_Components/Smallbox.md

docs/images/examples_alert.png

docs/images/examples_badge.png

docs/images/examples_button.png

docs/images/examples_callout.png

docs/images/examples_card.png

docs/images/examples_infobox.png

docs/images/examples_smallbox.png