Resume the review of https://github.com/eclipse-che/che-docs/pull/2553, which was forked and evolved into https://github.com/eclipse-che/che-docs/pull/2555/ during a pre-merge scan when a merge and backports were requested by Ilya.

Editing required during review, opening a PR with the edit.

Rendering issues need some fixing (unexpected highlighting, missing hashes, monospace where bold should be used, etc.):

https://63f48c209e215930a0aecafe--eclipse-che-docs-pr.netlify.app/docs/next/administration-guide/removing-user-data/

Other edits done as well like adding the warning about adverse effects of data removal, replacing the Wikipedia link with an official website, rewriting the first two steps as one after a clarification in the chat, incorporating the previous admonition content into the steps, colon instead of a period, etc.