fix kafka hostname

[thiagodpf]

• Please check if the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

bug fix

• What is the current behavior? (You can also link to an open issue here)

When the kafka container is destroyed and a new container is created, the host name changes and this causes the V2K to not be able to take mqtt messages from verne to kafka.

• What is the new behavior (if this is a feature change)?

When the kafka container is destroyed and a new container is created, the host name must be the same.

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

no

• Is there any issue related to this PR in other repository? (such as dojot/dojot)

This problem started to occur after the volumes were mapped on the docker-compose:
dojot/dojot#1585
dojot/dojot#1484

• Other information:

[rascaraficci]

It looks OK!