NSO operations can take much longer than 10 seconds as they operate on
real network equipment, set default timeout to 5 minutes and allow for
user override.
* move set_module_args to units.modules.utils
* unit tests: reuse set_module_args
* unit tests: mock exit/fail_json in module.utils.ModuleTestCase
* unit tests: use module.utils.ModuleTestCase
* unit tests: fix 'import shadowed by loop variable'
