Feature: Make -u argument optional in CLI.

[amovar18]

Description

This PR aims to add a default argument to the CLI which will be the website URL and will allow the user to analyse the website without requiring to use the -u option. If the user wants to use the -u option, it will still be available.

Relevant Technical Choices

• Add optional argument using .argument function from commander.js

Testing Instructions

• Clone this branch.
• In the terminal run npm run cli:build.
• Now in the terminal run npm run cli https://bbc.com.
• This should analyse bbc.com website.

Additional Information:

Screenshot/Screencast

https://github.com/GoogleChromeLabs/ps-analysis-tool/assets/59614577/89826e59-4d24-475a-9b28-f31ca4a6df70

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Checklist

• [x] I have thoroughly tested this code to the best of my abilities.
• [x] I have reviewed the code myself before requesting a review.
• [ ] This code is covered by unit tests to verify that it works as intended.NA
• [x] The QA of this PR is done by a member of the QA team (to be checked by QA).