Photonic Power Model: Uml updates to align with committed Yang

[karthik-sethuraman]

• Refactored PowerPropertiesPac, LaserPropertiesPac & FecPropertiesPac classes to complex data-type
• Added PowerManagementCapabilityPac and PowerManagementConfigPac classes
• Added powerManagementCapability attribute to the OtsiSIPSpec and MediaChannelSIPSpec
• Added powerManagementConfig attribute to the MediaChannelCSEPSpec
• Minor re-ordering of few Yang RPC augment statements due to tool generation
• removed Link augment statement for power-loss-characteristic as TransferTimingPac in Topology has lossCharactersistic which can be used for now. The TopologyPacs are expected to be enhanced soon