Highlight how does SeaORM handle the classic N+1 problem

[VaZark]

Since SeaORM is not lazy and can use eager loading to fetch data, I'm assuming the classic N+1 problems that occur in most ORMs are completely sidestepped.

It will be useful for newcomers to learn how to use it if there is an explicit reference to the problem and the solution in the docs.

[tyt2y3]

Agreed. We should add some sections to the docs.