- Implement the std::fmt::Display trait for the structure table so the table is printed like in the [Usage](#usage) the length of each column must adjust to the longest element of the column and the element must be centered in the "cell" when possible, if the length of the element doesn't allow to center exactly it must alight slightly to the right.
- Note: If the table is empty `println!` must not print anything.
- Define the associated function `new` that create a new empty table.
- Define the method function `add_row` that adds a new row to the table created from a slice of strings.