Update per-layer capacitance with the results from segment-based regression across PDKs

[AcKoucher]

Description

The new segment-based regression should give us a more precise approximation of per-layer capacitance.

PDKs:

• asap7
• gf12
• gf180
• ihp
• nangate45
• sky130hd
• sky130hs

Suggested Solution

Run regression with the data of all the designs we run in our CI and evaluate GRT DRT timing discrepancies.

Additional Context

This should wait for #4243 to be closed.