Update README of LocalChat with clearer installation and running steps for tkinter

[gauritomar]

This PR updates the README to improve the clarity of the installation and running steps for projects utilizing tkinter. Specifically, it adds the command sudo apt-get install python3-tk to install tkinter, ensuring that users have the necessary dependencies before running the project. Additionally, it enhances the instructions to provide clearer guidance on how to install and run the project, enabling users to get started more efficiently. These changes aim to improve the usability and accessibility of the project for both new and experienced users.