Implement emplace* methods for QVector

There are no methods to construct elements in-place, such as "emplace" and "emplace_back".

The steps (sub tasks) for this user story should be:

1. Investigate if this is possible and makes sense (If you have already done this investigation, feel free to share!)
2. Implement "emplace"-like method to create an element at a given position in a vector (std::vector::emplace)
3. Implement "emplace_back"-like method to create an element at the end of a vector (std::vector::emplace_back)
4. Add unit tests and documentation for all cases