Added another feature-passing multiple dir paths

[sanji11]

As I mentioned on issue #13, I added a feature to pass multiple directory paths as an argument. To do that, first I made a new option which is called -d and --dir and the type is array so that we can pass one or more dir. Now, we have two options which requires handling to make sure at least one option is passed. Hence, I made a function to check for options and do action according to the option they passed.

The -n and -d options will read file eventually as a result I moved your fs.readFile into a separate function called proceesFile. To read multiple directory, I used a for loop and called fs.readdir which will return all the files. Then, we need another for loop to go through each file and call the processFile function.

To test my new feature, I made two new dir called test and test2 where each contains two files. The test is successful 🥳 Hope you like the features I added 😄. To be honest, I feel accomplished 🥰

[Supercraft888]

Thanks again! Your awesome!