feat(typedefs): add type definitions to the project

[ZachHaber]

🔗 Linked issue

❓ Type of change

• [x] 📖 Documentation (updates to the documentation or readme)
• [ ] 🐞 Bug fix (a non-breaking change that fixes an issue)
• [x] 👌 Enhancement (improving an existing functionality like performance)
• [x] ✨ New feature (a non-breaking change that adds functionality)
• [ ] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This sets up typescript definition support for the project allowing typescript users to use the library and improving documentation by putting the docs inside the IDE.

📝 Checklist

• [ ] I have linked an issue or discussion.
• [ ] I have updated the documentation accordingly.

[ZachHaber]

Note: This includes the types set up for #43. To remove those types, the VNode parts can be removed from ToastBody so it is defined as string only.