[TestEnv] Setup devlib modules based on board definition

Created by: derkling

For the set of known boards, we know which modules can be loaded. For example "hwmon" is quite likely required only by "TC2" and "Juno".

We could exploit the board definition at TestEnv initialization time to define the list of modules to initialize when the devlib target is build.

This should allow to simplify further the default configuration file as well as make some test more portable across different boards.