support for advertising color attribute for SR policy in pcep

Reference: https://datatracker.ietf.org/doc/html/draft-ietf-pce-segment-routing-policy-cp-06

Need support to initiate SR policy with color attribute from pcep controller. Kindly refer the above mentioned draft.

with the current existing pcep-sr support in ODL there is no provision to generate color attribute and even if the PCC generates auto color for the sr policy it will not be persistent on node reboot cases which hampers the service mapping functionality using the color. Kindly help us to resolve this case by adding provision to configure color for the sr policy from pce.