Add more lint rules

Add more rules for linting by updating this [file](https://github.com/ArabsInBlockchain/hardhat-template/blob/main/.solhint.json) You can know more about [solhint](https://protofire.github.io/solhint/). . Please don't forget to check our [contribution guideline](https://github.com/ArabsInBlockchain/hardhat-template/blob/main/CONTRIBUTING.md).