Enhance handling of multiple VT libraries in OR

[precisionmoon]

Description

When multiple VT liberty and LEF libraries are loaded, some guidance is needed to steer OR to use a particular VT library for a specific P&R step. For example, to use only LVT cells for CTS, clock_tree_synthesis -library lvt_library_name is needed.
We want to automatically infer different VT libraries from liberty and LEF such that options like -library are not needed.
When auto inference of VT libraries is not possible, we want a general way to configure VT libraries such that different engines like CTS, setup fixing, hold fixing, power recovery can make use of this information.

Suggested Solution

The new behavior should be somewhat similar to those from commercial tools.

Additional Context

No response