Enforce pylint in CI via tox

Enforce pylint in CI via tox

- ignore duplicate-code and fixme detection in pylint profile
  fixme comments are fine and dup warnings contain many false positives
- enforce pylint with a minimal output and a score of 10 in CI
- create a "pylint_full" tox profile to display complete output
  with duplicate-code and fixme detections
- specify version requirement >=2.6.0 for a correct support of options,
  especially the option --fail-under= to specify minimum score allowed

JIRA: TRNSPRTPCE-320
LF-JIRA: IT-23316
Signed-off-by: guillaume.lambert <guillaume.lambert@orange.com>
Change-Id: I41f218d7f33f1f620a3f3c4d442655bf1cfb4ded