Better shorthand methods

[g105b]

Using magic methods breaks a lot of IDEs and is not great API design. The get* getAll* insert* ideas from #20 are being dropped in favour of this simplified API:

$customer = $db->fetch("customer/getById", 123);
echo "Customer name is " . $customer->first_name;

$numberDeleted = $db->delete("customer/deleteOldCustomers", ["created_at" => new DateTime("-2 years")]);
echo "Deleted $numberDeleted customers!";