fix: 🐛 Add Graph-coloring algorithm

[yashksaini-coder]

✅ Closes: #1335

This pull request adds a C implementation of the graph coloring algorithm using a greedy approach and includes comprehensive documentation in the README.md file. The main changes involve adding the algorithm code in program.c and detailed documentation in README.md.

Code Implementation:

• The main function demonstrates the algorithm with an example graph.

Documentation:

• Added detailed documentation for the graph coloring algorithm, including a description, problem statement, solution approach, usage instructions, example, and limitations.

[yashksaini-coder]

@pankaj-bind can you review this PR, and add proper labels to it

[pankaj-bind]

Move this to Graph Algorithm folder

[yashksaini-coder]

Move this to Graph Algorithm folder

I have moved the folder to the Graph one

[yashksaini-coder]

@pankaj-bind can you review this PR now