Create fastlane query for siblinks

[Gozala]

Moved from (inkandswitch/ksp-browser#9 (comment))

Querying ksp for siblinks currently looks as follows:

query Siblinks {
  resource(url: "https://www.inkandswitch.com/local-first.html") {
    url
    sibLinks: links {
      ...sibLink
    }
  }
}

fragment sibLink on Link {
  target {
    url
    backLinks {
      ...backLink
    }
    tags {
      ...tag
    }
  }
}

fragment tag on Tag {
  name
}

fragment backLink on Link {
  kind
  identifier
  name
  title
  fragment
  location
  referrer {
    url
    info {
      title
      description
      cid
    }
    tags {
      ...tag
    }
  }
}

There are multiple problems with this:

1. n+1 SQL queries
   1. First query will get links from the resource (with passed url) to materialize corresponding resources.
   2. Then it will query each materialized resource for backlinks.
2. Resulted backlinks for each URL will contain resource for the passed URL itself. Which then on client we will have to filter out.

I don't want to spend time on optimizing this right now, but think we should expose another query endpoint to have something like:

query {
  siblinks(url: "https://www.inkandswitch.com/local-first.html") {
      ...sibLink
  }
}

Which in the KSP can accomplish this with single SQL query and exclude links for the passed url itself.