FEATURE: Modularise this application

[Vyvy-vi]

Having all the code in one place is messy, we can modularise the code a bit to make everything more readable and maintainable.
FastAPI supports APIRouters, which can help us in implementing a modular structure for the project.

Maybe this folder structure? -

.
└──  src
  ├── __init__.py
  ├── main.py
  ├── dependencies.py
  └── routers
    ├── __init__.py
    ├── coinflip.py
    ├── gifs.py
    ├── encouragements.py
    ├── jokes.py
    └── diceroll.py