title: TypeORM make innerJoinAndSelect field required in query returned type
body: <p>I'm using TypeORM to make sql queries to my database. Also using typescript.</p>
  <p>My problem is: when you make query with TypeORM, it returned type is Entity that you chose.</p>
  <p>So, in my entity, I have some field that is optional, but when I select this entity with inner join</p>
  <pre><code>query.createQueryBuilder('lol')
        .innerJoinAndSelect('lol.somefield', 's')
        .limit(1)
        .getOne()
  </code></pre>
  <p>I want that entity to be required in query returned type.</p>
  <p>Like:</p>
  <pre><code>interface LolEntity {
      id: number,
      somefield: SomeEntity | undefined
  }
  </code></pre>
  <p>becomes:</p>
  <pre><code>interface LolEntity {
      id: number,
      somefield: SomeEntity
  }
  </code></pre>
  <p>when I use <code>innerJoinAndSelect</code></p>