Add CI template field to project GraphQL type

What does this MR do?

Sample query

{
  project(fullPath: "matteeyah/helloworld") {
    name
    ciTemplate(name: "Android") {
      name
      content
    }
  }
}

{
  "data": {
    "project": {
      "name": "helloworld",
      "ciTemplate": {
        "name": "Android",
        "content": "..."
      }
    }
  }
}

Related #328802 (closed)

Does this MR meet the acceptance criteria?

Conformity

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