Allow Karaf to listen to an alternative SSH port

Allow Karaf to listen to an alternative SSH port

In Karaf post-install script for tests
- generate a configuration file template for Karaf Shell
- patch Karaf exec to generate configuration file from environment
  variable and template

In tox.ini
- declare the related variable in SETENV parameters

Allowing the controller configuration to listen to alternative ports
is a commodity to run functional tests in parallel.

JIRA: TRNSPRTPCE-482
Signed-off-by: guillaume.lambert <guillaume.lambert@orange.com>
Change-Id: Id1b367aaaaccae4bcf74d1b6ac0aa4997f3083a6