Child of constraint impovement for animation.

Problem: The offset matrix in child of constraint cannot be dynamically modified, if you create an animation where you need to turn a constraint on/off, any time you modify another bone that is associated with that constraint, the positions when turning off the constraint need to be changed every time, which turns the creative process of animating into a dull routine. Probably solutions:

1. The offset position of the constraint should be animated, at least it would be possible to insert a driver to control the position from other places.
2. Automatic determination of offset by the constraint itself when working with nla: every time we turn on/off the constraint, it should automatically determine the positions in relation to where the original bone and the parent are located, so that there are no unwanted movements.

In general terms, I want working with dynamic parenting to be less destructive, so that for example if I have a strip with animation where there is a constraint on or off, by moving it freely, its effect will be visible, but there will be no current problems with displacement due to the built-in matrices into a constraint.