Issue 4689: Add option to copy parts of JSON data

Steps to reproduce

  1. Enable the Console & Net panels
  2. Select the Console panel
  3. Enable the "Show XMLHttpRequests" option
  4. Click this button:
  5. Choose i or ii
    1. In the Console panel click on the first request (data.json) and then press the JSON tab
    2. In the Net panel click on the request containing 'data.json' and then press the JSON tab
  6. Right click on 0 and choose 'Copy "0" as JSON'
  7. Check system clipboard

Expected result