Improvements to Code and Readme

[cherriae]

Added:

valorant.structs.__init__.py:

from .account import *
from .agent import *
from .leaderboard import *
from .loadout import *
from .match import *
from .structs import *
from .user import *

This is so that you don't have to import file by file but import just from the directory

Improved README.md to be more user friendly.

• Add contributions section
• Improve header
• Add emojis to titles