Add template for TypeScript environment variables

[keonik]

I forsee others will run into a similar extension of environment variables. This would be good to add a types.d.ts file to make this extension easier

Example

import { PrismaClient } from './lib/prisma';
import { Client as MinioClient } from 'minio';

declare global {
    namespace NodeJS {
        interface ProcessEnv {
            NODE_ENV: 'development' | 'production';
            PORT?: string;
            DATABASE_URL: string;
            ENVIRONMENT: 'prod' | 'edge' | 'uat';
            MINIO_SECRET: string;
            MINIO_ACCESS: string;
            MINIO_ENDPOINT: string;
            MINIO_SSL: string;
            GOOGLE_ANALYTICS_ID: string;
            NEXTAUTH_URL: string;
        }
    }
}

export {};