No inherent support for Undirected Graphs

[Akshat-Shu]

In it's current state, the library does not seem to provide any inherent support for undirected graphs.

Description
Currently, users must add an edge and a reverse edge manually in order to form a undirected graph which is prone to errors.

Expected Behaviour

• When adding an edge (u, v), the library should automatically add (v, u) if the graph is undirected.
• Ensure that operations like removing edges, traversals, and adjacency checks work seamlessly for undirected graphs.
• Support for undirected mode in graphs so that algorithms meant specifically for undirected graphs can flag wrong inputs