Move to more idiomatic GraphQL API query and response structure

[deekerno]

Our GraphQL API responses are pretty good right now, but as we move to being used by the public, we should try to adhere to common practices or idioms where we can.

The following query is from @luizstacio, and contains what I feel should be a good starting query and response structure:

query {
  transactions(first:10) {
    nodes {
      id
    }
    pageInfo {
      hasPreviousPage
    }
  }
  blocks(first:10) {
    nodes {
      id
    }
    pageInfo {
      hasPreviousPage
    }
  }
}

The requisite sub-issues are:

• Change paginated API query metadata to only be included in response if requested #791
• Allow for multiple queries inside of a GraphQL API request #792
• Change entity fields in GraphQL API request to be queryable under nodes object #793

[ra0x3]

Gonna close.

• Things we're gonna implement tracked in GraphQL implementable functionality  #937
• Things we're aware of but not gonna implement at this time tracked in GraphQL extended functionality #935