Javascript methods for page modification

[AuroraLS3]

Split from Page Extension API #1288

Feature 3: Javascript methods for easy modification

As an API user I should be able to..

• [ ] Make a XMLHTTPRequest to the Plan webserver
  • [ ] Have a json callback
  • [ ] Have an XMLHTTPRequest callback (for non json)
• [ ] Select a tab I wish to append content to
• [ ] Append content to a tab
• [ ] Select a card I wish to append content to
  • [ ] Append content to a table in specific position
  • [ ] Append content to a text-list in specific position
• [ ] Add a new tab div with an id
• [ ] Add a new navigation link to a tab id or URL
  • [ ] With an icon
  • [ ] Add a collapsible navigation block (with more links inside it)
• [ ] Generate Plan-like html
  • [ ] Text with colored icon next to it
  • [ ] Table row
  • [ ] Colored button with an icon
• [ ] Have a document with Plan-like html as a reference