gateway: status: add gatewayhost to event wrapper

[gioelecerati]

What does this pull request do? Explain your changes. (required)

Specific updates (required)

• Add gateway_host to event wrapper
• KafkaConfig instead of sending all the stuff as parameters when initializing the kafka producer

How did you test each of these updates (required)

Does this pull request close any open issues?

Checklist:

• Read the contribution guide
• make runs successfully
• All tests in ./test.sh pass
• README and other documentation updated
• Pending changelog updated

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 26 lines in your changes missing coverage. Please review.

Project coverage is 33.91248%. Comparing base (a842a0d) to head (a0f2725).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
monitor/kafka.go	0.00000%	16 Missing ⚠️
cmd/livepeer/starter/kafka.go	0.00000%	10 Missing ⚠️

Additional details and impacted files

@@                 Coverage Diff                 @@
##              master       #3323         +/-   ##
===================================================
- Coverage   33.92247%   33.91248%   -0.00999%     
===================================================
  Files            141         141                 
  Lines          37173       37181          +8     
===================================================
- Hits           12610       12609          -1     
- Misses         23843       23852          +9     
  Partials         720         720                 

Files with missing lines	Coverage Δ
cmd/livepeer/starter/kafka.go	0.00000% <0.00000%> (ø)
monitor/kafka.go	0.00000% <0.00000%> (ø)

... and 1 file with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3ac5972...a0f2725. Read the comment docs.

Files with missing lines	Coverage Δ
cmd/livepeer/starter/kafka.go	0.00000% <0.00000%> (ø)
monitor/kafka.go	0.00000% <0.00000%> (ø)

... and 1 file with indirect coverage changes