fix(logUtils): honour the documented `console` argument; ETSI_QUIET_IO=1 keeps...

It will generate a specific `errors.log` file into the `results` folder with the description of the different steps 

developed and the mismatched observed on them.

### Keep the requests and responses out of the terminal

Every request and response is written to the terminal as well as to `log.html`. On a full run that is thousands of

them. With `ETSI_QUIET_IO=1` they go to `log.html` and `output.xml` only, and the terminal shows one line per Test

Case:

```ETSI_QUIET_IO=1 robot --outputdir ./results ./TP/NGSI-LD```

The `Output` and `Output Notification` keywords also take `console=${False}` for a single call.

### Measure the API coverage of a run

[scripts/api_coverage](./scripts/api_coverage) counts, from a run's `output.xml`, which operations of the NGSI-LD

from __future__ import unicode_literals

from __future__ import division

from json import dumps, JSONDecodeError, loads

from os import environ

from robot.api import logger

from robot.api.deco import keyword

def _to_console(console):

    """Should this be echoed to the terminal?

    The `console` argument of the keywords below is documented ("If false, the

    JSON is not written to terminal") and was ignored - every request and every

    response went to the terminal. On a full run that is thousands of

    request/response pairs, which bury the one line per test that tells what

    happened.

    ETSI_QUIET_IO=1 switches the echo off for the whole run, without touching a

    test. Nothing is lost: logger.info always writes to log.html and output.xml.

    `console` may come from Robot as a string ("False", "no", "0", "off").

    """

    if environ.get("ETSI_QUIET_IO") == "1":

        return False

    if isinstance(console, str):

        return console.strip().lower() not in ("false", "no", "0", "off", "")

    return bool(console)

@keyword(name="Output", tags=("I/O",))

def output(response, description, console=True):

    """*Request and response are output to terminal and file (in JSON).*

    pretty_request_json = dumps(request_json, indent=4, sort_keys=False, separators=(",", ": "))

    pretty_response_json = dumps(response_json, indent=4, sort_keys=False, separators=(",", ": "))

    logger.info("\n" + description, also_console=True)

    logger.info("Request ->", also_console=True)

    logger.info(pretty_request_json, also_console=True)

    logger.info("Response ->", also_console=True)

    logger.info(pretty_response_json, also_console=True)

    echo = _to_console(console)

    logger.info("\n" + description, also_console=echo)

    logger.info("Request ->", also_console=echo)

    logger.info(pretty_request_json, also_console=echo)

    logger.info("Response ->", also_console=echo)

    logger.info(pretty_response_json, also_console=echo)

@keyword(name="Output Notification", tags=("I/O",))

    pretty_request_json = dumps(request_json, indent=4, sort_keys=False, separators=(",", ": "))

    logger.info("\n" + description, also_console=True)

    logger.info("Notification ->", also_console=True)

    logger.info(pretty_request_json, also_console=True)

    echo = _to_console(console)

    logger.info("\n" + description, also_console=echo)

    logger.info("Notification ->", also_console=echo)

    logger.info(pretty_request_json, also_console=echo)