Publish the map to /map

[m2-farzan]

Hey, thanks for this great work.

I'm using OpenVSLAM 0.3.0 on ros2.

My question is, is it possible to have the map published to /map topic so that other packages like nav2 can use it for path planning?

If such a feature doesn't exist, do you think it's worth implementing? I could give it a try. I'm thinking of an optional cli argument for run_slam that when provided, publishes the map to /map. The challenging part seems to be to convert the map from the msg format to nav_msgs::OccupancyGrid.