Added option to turn shared subscription off or change the group identifier

[fbuedding]

Twin PR, same changes.

[AlvaroVega]

the code of this file was tainted, but no really changes?

[fbuedding]

This is due linting and/or prettier. I just ran the scripts defined in the package.json

[AlvaroVega]

command could be modified in line 99

[fbuedding]

Also linitng and prettier

[AlvaroVega]

Maybe new configuration option about disable shared subscription should be also added an explained into: https://github.com/telefonicaid/iotagent-json/blob/master/docs/installationguide.md#mqtt-configuration
In which cases disable shared subscription is a good idea?

[fbuedding]

As described in the twin PR I only really changed the following files:

• test/unit/startup-test.js
• test/unit/ngsiv2/configurationsMqtt-test.js
• lib/configService.js
• lib/bindings/MQTTBinding.js
• docs/usermanual.md
• docs/installationguide.md

[AlvaroVega]

telefonicaid/iotagent-ul#624 (comment)

[fbuedding]

Honestly no idea why the test is failing or timing out, here are my test results

(16.x):

129 passing (13s)
3 pending

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	83.18	68.97	86.58	82.97
lib	86.46	82.12	85.89	86.21
commandHandler.js	90.47	72.22	100	90.16	46-47,59,153-161,165
commonBindings.js	96.49	85.71	100	96.33	70,304-306
configService.js	93.54	91.91	100	93.49	49-50,150,153,156,225,229,233
constants.js	100	100	100	100
errors.js	13.33	100	10	13.33	33-100
iotaUtils.js	83.33	73.01	100	83.13	46-47,58-59,118-119,172,179,197-208,224,228-237
iotagent-json.js	82.69	66.66	84.61	82.69	94,110,128,166-172
transportSelector.js	100	100	100	100
lib/bindings	80.11	56.84	87.2	79.96
AMQPBinding.js	76.85	43.47	88.88	76.85	75,78,84,90,98,105,110,118,121-123,135,142-145,149-150,156-159,176,214,259
HTTPBinding.js	77.94	62.25	86.66	77.69	...-160,164,200,213,227-236,262-263,345,353,381,383,406,408,418,425,440-448,523,555,562-565,571,579,593-597,658-663,681-705
MQTTBinding.js	86.48	54.54	86.95	86.39	141-143,169,172,194,232,235,267,276-279,284-286,295,298,323,401,423

(18.x)

129 passing (13s)
3 pending

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	83.38	68.97	86.58	83.16
lib	86.46	82.12	85.89	86.21
commandHandler.js	90.47	72.22	100	90.16	46-47,59,153-161,165
commonBindings.js	96.49	85.71	100	96.33	70,304-306
configService.js	93.54	91.91	100	93.49	49-50,150,153,156,225,229,233
constants.js	100	100	100	100
errors.js	13.33	100	10	13.33	33-100
iotaUtils.js	83.33	73.01	100	83.13	46-47,58-59,118-119,172,179,197-208,224,228-237
iotagent-json.js	82.69	66.66	84.61	82.69	94,110,128,166-172
transportSelector.js	100	100	100	100
lib/bindings	80.49	56.84	87.2	80.34
AMQPBinding.js	76.85	43.47	88.88	76.85	75,78,84,90,98,105,110,118,121-123,135,142-145,149-150,156-159,176,214,259
HTTPBinding.js	77.94	62.25	86.66	77.69	...-160,164,200,213,227-236,262-263,345,353,381,383,406,408,418,425,440-448,523,555,562-565,571,579,593-597,658-663,681-705
MQTTBinding.js	87.83	54.54	86.95	87.75	169,172,194,208,232,235,267,276-279,284-286,295,298,323,401,423