Moved bot invite link to .env and added an install script for Linux

[DarrenAlex]

Changelog

• Moved BOT_INVITE_LINK to .env
• Added install.sh
• Updated README.md
• Updated emoji IDs to universal IDs

Features of install.sh:

• Choose which packages to install (if you already have them)
• Make a restart.sh script to restart the bot if anything goes wrong
• Automatically fill the values in .env from user input
• Deploy an instance of the bot rapidly and quickly

[DarrenAlex]

AmongUsClient has been updated for the newest AU version. README.md has been updated too. Note for self: I need to stop commiting so much