Backport the autoSplitVector logic to v4.0

Objective of this ticket is:

• Backporting the autoSplitVector function (basically copying auto_split_vector.h and auto_split_vector.cpp and the relative unit tests.
• Backporting the autoSplitVector command
• Replacing the internal usages of splitVector with autoSplitVector
• Adapt the tests expecting exact number of split points according to the new logic