Added quick generate options in Extension context menu

[manthanabc]

Adds three new options to context menu

• Generate MCQ questions
• Generate true/ false type questions
• Generate short questions

Each options use default value for difficulty and question numbers and effectively skips the text-input page, to allow users to quickly generate questions.

Video demo-

recording.1.mp4

This PR also does some cleanup from other extension related code like

• Removes the contentScript
  justification: It was redundant since chrome.storage.local is specific to extension it can be directly accessed by the background service worker script (background.js) and there is no need to pass around messages to a content script for it to just do the same again
• Fixes indentation in background.js file

[Roaster05]

@Aditya062003 this PR seems fine to me , have a look at it once