Added first version of database update script under `\db_update` directory

[CoToYo]

Description

1. Added first version of database update script under \db_update directory.
2. Setup MongoDB Atlas database for cyber news storage

For now, Python package cybernews will be used for fetching news data from the Internet and to the database. Once the part of API service is completed, this part (news db updating) will begin by implementing web scraping logic based on the code of cybernews pacakge.

Related Issue

Motivation and Context

According to the new design, a separate service is needed for updating the knowledge base of cyber news.

This service should be run separately and periodically as a scheduled task while the API service is running continuously as web service for listening requests from users.

Therefore, a new directory \db_update was created for it.

How Has This Been Tested?

Screenshots (if appropriate):

News were successfully written into the database, which prove the functionality of the db update script works normally.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.