Fixed incorrectly SubEditList ReadOnly attribute storage; refactoring (#1580)

Fixed incorrectly SubEditList ReadOnly attribute storage; refactoring (#1580)

Originally SubEditList uses std::set<bool> m_readOnlyColumns storage for read-only columns.
Expectedly int-type should be used instead of bool-type if we want to make any particular (not only 0-index) column work in read-only mode or it doesn't have any sense to use std::set at all. Original code doesn't produce any issue because that function used in one place (I hope) with index 0 only, respectively 0-column only read-only and any other does not.
Code refactored to eliminate usage of 2 redundant std::set storages for 2 different attributes and used one only std::vector to store and read_only+boolean_value type and EditStyle.