feat: improved query logging

[schwma]

This PR contains the following changes

- Improved query logging:
  + Don't log queries that are `undefined`
  + Log `operationName`
  + Log `variables` when not in production
  + Sanitize arguments and their values in queries when in production

Explanation:

• Requests that load the GraphiQL web client, i.e. GET /graphiql would log GET undefined which was confusing.
• Without the operationName it was impossible to know which query was executed when the payload contains more than one query.
• Variables were previously not logged (only literal values as they inline in the query). This made development less convenient.
• Literal values (values specified inline for arguments) were previously logged, even in production. These values could contain sensitive information not meant for logs, such as values specified during create and update mutations. Arguments and their values are now sanitized in production for literal values as well as variables.

Example

Query:

query ListAllBooks {
  AdminService {
    Books {
      nodes {
        title
      }
    }
  }
}

query ListFilteredBooks ($filter: [AdminService_Books_filter]) {
  AdminService {
    Books(filter: $filter) {
      nodes {
        title
      }
    }
  }
}

with variables:

{ "filter": { "ID": { "ge": 250 } } }

and

"operationName": "ListFilteredBooks"

Previous log output

[graphql] - POST query ListAllBooks {
  AdminService {
    Books {
      nodes {
        title
      }
    }
  }
}

query ListFilteredBooks ($filter: [AdminService_Books_filter]) {
  AdminService {
    Books(filter: $filter) {
      nodes {
        title
      }
    }
  }
}

New log output

During development:

[graphql] - POST {
  operationName: 'ListFilteredBooks',
  variables: { filter: { ID: { ge: 250 } } }
} 
query ListAllBooks {
  AdminService {
    Books {
      nodes {
        title
      }
    }
  }
}

query ListFilteredBooks ($filter: [AdminService_Books_filter]) {
  AdminService {
    Books(filter: $filter) {
      nodes {
        title
      }
    }
  }
}

In production:

[graphql] - POST { operationName: 'ListFilteredBooks', variables: '***' } 
query ListAllBooks {
  AdminService {
    Books {
      nodes {
        title
      }
    }
  }
}

query ListFilteredBooks ( *** ) {
  AdminService {
    Books( *** ) {
      nodes {
        title
      }
    }
  }
}

[schwma]

@hm23 btw, since we were talking about this: This is a way to deploy to SQLite in-memory with cds.test, even if NODE_ENV=production is set.