Clock Propagation Changes

[kareefardi]

• OpenROAD.*STA*:
  • Don't set propagated clock outside of the sdc
  • Move set propagated clock inside the default sdc file
  • Add backwards compatible behavior to use set propagated clock outside of the sdc in case the sdc doesn't propagate any clocks explicitly
  • Report nonpropagated clocks
  • Report some information about clocks