Notify workhorse about etag changes

Open Kamil Trzcińśki requested to merge notify-workhorse-about-etag-cache-changes into master

What does this MR do?

Makes E-tag caching to notify about resource changes.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

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