Add webPath and editPath to group and project GraphQL types

What does this MR do and why?

Related to &13790 (closed)

We use GraphQL queries for group and project lists and we want to avoid constructing relative URLs on the frontend due to problems with relative URL configuration. This MR makes available two fields on group and project types:

• webPath
• editPath

Screenshots or screen recordings

How to set up and validate locally

1. (Optional) add relative_url_root: '/gitlab' to gdk.yml. Then run gdk reconfigure && gdk restart
2. Go to http://127.0.0.1:3000/gitlab/-/graphql-explorer or http://127.0.0.1:3000/-/graphql-explorer depending on if you did step 1
3. Run the following query

query {
  projects(first: 1) {
    nodes {
      webPath
      editPath
    }
  }
  groups(first: 1) {
    nodes {
      webPath
      editPath
    }
  }
}

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