Launches rviz2 for visualization of algorithms and 
         map_node which provided the preliminary data

Has the preliminary map defined.
Publishes 
    Map with obstacles
    initial and goal pose embedded within the map

    map data is first stored in 2d matrix represented as x, y

Instead of adjacency list, the preliminary map is transmitted.
    
Serves service `get_map` requested by individual algorithms for preliminary map.
Since this wont be changing over time and will be required only once service has been used,
instead of topic.

Waits for the GetMap service and requests the service for map with obstacles with initial and goal pose.
Instead of using sync service, using a flag to wait for the response.

Service callback method converts the data into 2D matrix for manipulation.

Within the timer loop BFS traversal is performed and each node is marked visited denoted in the map itself. 
After each iteration of master loop color of visited cells is increased in spectrum for visualization.

Path is back tracked using `parent` attribute and path is generated.

-128 to -2 => RED to YELLOW
-1         => GREY
0          => BLACK
1 to 98    => BLUE to RED
99         => CYAN
100        => PINK
101 to 127 => GREEN

YELLOW => START POINT
BLUE   => END POINT
GREEN  => GENERATED PATH
Explored area has a gradient from YELLOW to BLUE for each iteration.