Update openconfig-transport-line-protection.yang

[zyboy2000]

hello, i work in an optical commpany ,very interested in optical yang module, make some suggestions,hope to adopt!

1. Add APS_MODE, it includes APS_AUTOREV, APS_AUTONOREV,APS_FORCE, APS_MANUAL .
2. Add return-timer and switch-timer
3. Add common-in-alarm-threshold and common-out-alarm-threshold
4. Add primary-alarm-threshold and secondary-alarm-threshold