Script to do all the file and variable renaming

In the [installation steps: step 2](https://github.com/abhishek-pokhriyal/wp-plugin-boilerplate#installation--getting-started), a lot of renaming (file names and variable names) is required before we can get started to the development.

### Possible solution

We can probably write a shell script to automate this process. To get an idea, in the WooCommerce plugin there is [bin](https://github.com/woocommerce/woocommerce/tree/master/bin) directory that holds the script for handling common tasks.

These scripts are then [referenced in package.json](https://github.com/woocommerce/woocommerce/blob/0d3889a36056b2457da537301b168c0fc06cc945/package.json#L17).

So, running `npm build` in WooCommerce project will create a zip version of the plugin.