Refactor PCE network analyzer PceOtnNode step 2

Refactor PCE network analyzer PceOtnNode step 2

second pass to prepare deeper refactoring of PceOtnNode class:
- use Map or List to check and manage ODU and Eth service types
  instead of switch/case and if condition blocks with multiple checks
- rationalize namespaces use and import
- refactor a few checks and indentations
- point with TODO comments places where
  * some missing service types might be managed
  * some checks are similar to existing methods
  * some new methods would help

JIRA: TRNSPRTPCE-572
Signed-off-by: guillaume.lambert <guillaume.lambert@orange.com>
Change-Id: I4ede34d4d55895303abee95365e232e97fc91de5