[Feature request] Support monorepos in integration catalog

[benedfit]

Describe the bug

Currently when adding items to the integration catalog, addons that are stored in monorepos do not current display the correct information

Steps to reproduce the behavior

1. Go to https://storybook.js.org/addons/@newhighsco/storybook-addon-svgr/
2. See that the README is not available
3. Click on "View in Github"
4. See that you land on https://github.com/newhighsco/storybook, the monorepo root, rather than the directory that contains the addon

Expected behavior

The package.json for @newhighsco/storybook-addon-svg contains details of the directory that contains the source and README - https://github.com/newhighsco/storybook/blob/0d6c60da90e33ba609da122c429e3af4932ec320/packages/storybook-addon-svgr/package.json#L15-L19:

"repository": {
    "type": "git",
    "url": "https://github.com/newhighsco/storybook.git",
    "directory": "packages/storybook-addon-svgr"
 }

It would be great is the integration catalog could use the additional directory information, use it to find the README and append it to the "View in Github" href