Script to update duration using json data

[Abhishek-1337]

PR Fixes:

• 1 Uses json file to update duration field in VideoMetaData table.

Resolves #390

Checklist before requesting a review

• [x ] I have performed a self-review of my code
• [ ] I assure there is no similar/duplicate pull request regarding same issue

This is my first time I completed something in this repo. Some days ago I took whole day to understand the database of the application and when I saw this issue, I immediately started working on it and previous knowledge of database helped me. There's already a PR and its better than mine in lot of ways I guess but I wanted to show you my work.