Feature/tags for elasticsearchwriter

[SebastianOpeni]

Offers to add additional tags to entries written by the ElasticSearchWriter.

As discussed with Eric at the icinga summit we are submitting this feature. Please revise the code and let us know if there is something we need to improve. otherwise we would be happy for timely merge.

fixes #6837

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[ngoeddel-openi]

lgtm

[SebastianOpeni]

The CLA should be signed now.

[bobapple]

@cla-bot check

[yhabteab]

Hi, thanks for your contribution! I've just been looking over the code changes and left some inline comments below, but haven't tested it with an Elastic/OpenSearch instance yet. Other than that, can you please rebase this against the current master to fix the GitHub actions. Thanks!

[SebastianOpeni]

Hi thanks for your review :)
I am currently working on your remarks but might have some questions beforehand.

[SebastianOpeni]

Thanks for your answers in the review.
I tried to implement everything as requested.

[yhabteab]

Apart from #10074 (comment), code wise it should be fine now, I haven't tested it with a actual ElasticSearch instance though, but till I get the time, some of my colleagues might want a look at this as well.

[yhabteab]

I tested this today with ElasticSearch 7.17.25 and it seems to be working fine 👍🏼. Though , whilst going through the changes again, I just noticed two small things, see inline comments below.

Edit: While you're at it, please rebase this against the master branch to get the GHAs pass.