Aruco code visualisation

[KatherineZT]

Add a way to visualise the Aruco codes that are detected by the rover (by subscribing to /aruco topic).

• Add a "landmarks" section in the portal where the Aruco codes can be shown (a little bit like the interest points)
• Make the "landmarks" section subscribe to the /aruco topic with roslib
• Support the custom message type for the topic
• Test to see if it works!