make OTN PCE code work with the right parameters

The various OTN services shall run with otn-topology:

• ODU4 structured for LO-ODU
• 100Ge relying on ODU4 not structured
• 10Ge/OTU2/1Ge relying on LO-ODU (ODU2e/ODU2/ODU0)

This includes the consolidation of the code for Xponder/tp validation.
A function that checks the presence of OTN links (OTU4 for ODU4 creation), and of trib-slots in in xpdr-tp-port-connection-attributes (present for LO ODU creation, absent for ODU4 creation) shall be developped.

functional tests in another item

Evaluation indicator:

• code published on master branch , not necessarily merged
• build , no new warnings, functional tests passed