Initial ROS2 Port

[suchetanrs]

Apart from the full Port to ROS2, A simple publisher is added at the end which subscribes to the "map" topic and publishes the frontier centroid and intial points. I made this change for an initial demo. I will remove this once the costmap plugin is ported. The overflow update bounds in the costmap is fixed as well.

Please do have a look when you have time :)

[suchetanrs]

Hi @paulbovbel!

I found the time last month to work on this again :) I started with porting the indigo branch first because it was simpler and all the files were in one place. I've tested the full port and it seems to be working fine on ROS2 Humble. Since this development was done over a long period of time and in the process there have been quite some changes/ fixes, a lot of format issues have come up because I used a default formatter that I had in place. I am not sure if its feasible for you to verify each change I did with all the format issues in between. What can we do for this? I don't know yet but I feel even if the format issues are fixed, there will still be a lot of changes since I've refactored a part of the code to make it more readable. Would you want to add a default formatter for the code or just maintain the ROS2 branch separately all together? :)