recent_content: Plugin structure

(ActionItem2848)

Signed-off-by: Marcos Ramos <ms.ramos@outlook.com>
blog: added cover image for blog

(ActionItem2849)

Signed-off-by: Marcos Ramos <ms.ramos@outlook.com
Signed-off-by: Valéssio Brito <contato@valessiobrito.com.br>
recent_content: rendering enhacement, style css, and tests.

(ActionItem2848)

Signed-off-by: David Carlos <ddavidcarlos1392@gmail.com>
Signed-off-by: Gabriela Navarro <navarro1703@gmail.com>
Signed-off-by: Marcos Ramos <ms.ramos@outlook.com>
Signed-off-by: Valessio Brito <contato@valessiobrito.com.br>