Adding MulCompensation Nodes in the PTQ pipeline

During the single-shift approximation, the PTQ pipeline inserts "compensation nodes" to rebalance input values. These nodes are simple multiplication (Mul) operations. However, if a user provides a model that already includes Mul nodes, they may be misinterpreted as compensation nodes, which could disrupt the PTQ pipeline.

To address this issue, I propose introducing a new meta-operator, MulCompensation. This operator would encapsulate a single Mul operation (similar to the Scaling meta-operator) and serve as a clear tag for these specific compensation nodes. In the future, it might be more efficient to replace meta-operators containing a single unitary operation with the corresponding operation and an appropriate attribute.