Propagate `--loglevel` to yadage backend

[danikam]

The yadage INFO output from the recast-run is the same regardless of the --loglevel option given to the run command. Eg. using the helloworld example,

recast --loglevel DEBUG run examples/helloworld --backend docker

and

recast --loglevel CRITICAL run examples/helloworld --backend docker

give the same output:

2020-03-24 18:00:53,276 | packtivity.asyncback |   INFO | configured pool size to 2
2020-03-24 18:00:53,379 |      yadage.creators |   INFO | initializing workflow with initdata: {'name': 'hello'} discover: True relative: True
2020-03-24 18:00:53,381 |    adage.pollingexec |   INFO | preparing adage coroutine.
2020-03-24 18:00:53,381 |                adage |   INFO | starting state loop.
2020-03-24 18:00:53,450 |     yadage.wflowview |   INFO | added </init:0|defined|unknown>
2020-03-24 18:00:53,624 |     yadage.wflowview |   INFO | added </hello_world:0|defined|unknown>
2020-03-24 18:00:53,733 |    adage.pollingexec |   INFO | submitting nodes [</init:0|defined|known>]
2020-03-24 18:00:53,789 |       pack.init.step |   INFO | publishing data: <TypedLeafs: {u'name': u'hello'}>
2020-03-24 18:00:53,790 |                adage |   INFO | unsubmittable: 0 | submitted: 0 | successful: 0 | failed: 0 | total: 2 | open rules: 0 | applied rules: 2
2020-03-24 18:00:53,927 |           adage.node |   INFO | node ready </init:0|success|known>
2020-03-24 18:00:53,927 |    adage.pollingexec |   INFO | submitting nodes [</hello_world:0|defined|known>]
2020-03-24 18:00:53,933 | pack.hello_world.ste |   INFO | starting file logging for topic: step
2020-03-24 18:00:58,521 |           adage.node |   INFO | node ready </hello_world:0|success|known>
2020-03-24 18:00:58,544 | adage.controllerutil |   INFO | no nodes can be run anymore and no rules are applicable
2020-03-24 18:00:58,545 | adage.controllerutil |   INFO | no nodes can be run anymore and no rules are applicable
2020-03-24 18:00:58,547 |                adage |   INFO | unsubmittable: 0 | submitted: 0 | successful: 2 | failed: 0 | total: 2 | open rules: 0 | applied rules: 2
2020-03-24 18:01:05,406 |                adage |   INFO | adage state loop done.
2020-03-24 18:01:05,407 |                adage |   INFO | execution valid. (in terms of execution order)
2020-03-24 18:01:05,407 |                adage |   INFO | workflow completed successfully.
2020-03-24 18:01:05,408 |  yadage.steering_api |   INFO | done. dumping workflow to disk.
2020-03-24 18:01:05,418 |  yadage.steering_api |   INFO | visualizing workflow.

RECAST result examples/helloworld recast-6626ff86:
--------------
- name: My Result
  value: Hello my Name is hello

Is it possible to propagate the --loglevel specification to the yadage backend logging?