Refactor PCE network analyzer PceOtnNode step 1

Refactor PCE network analyzer PceOtnNode step 1

first pass to prepare deeper refactoring of PceOtnNode class:
- fix a few typos
- fix most indentation issues
- remove useless parenthesis
- remove some useless intermediate variables
- remove all @Nullable decorators
  the presence of side null checks made most of them pointless
- review some if/else blocks/condition layout
- review some else-if and switch/block structures (1st pass)

JIRA: TRNSPRTPCE-572
Signed-off-by: guillaume.lambert <guillaume.lambert@orange.com>
Change-Id: If4c7fd58bc95d3fb9896f874df602d5f2b5ef9ee