Use environment variable to configure OLM timers

Creation of services with TransportPCE controller on real optical devices takes a rather long while, due to the fact that the output optical power level modification on interfaces requires stabilisation time. Per default values, recommended by OpenROADM MSA are respectively 120 000 and 20 000 seconds.
When running TransportPCE controller with honeynode simulators, which is the case of all TransportPCE functional tests, we don't need so important timer values. We can considerably speed tests using respectively 3000 and 2000 seconds.
Currently, this timer values are automatically modified by tox, so only in the virtual environment, with a post compilation script.
It would be more relevant to have olm timer values depending on specific environment variables set or not on the system when we start karaf.