Documented ingeter migration to spread-minimizing tokens

[duricanikolic]

What this PR does

This PR adds a documentation on how to migrate ingesters to spread-minimizing tokens.

Which issue(s) this PR fixes or relates to

Part of #4736

Checklist

• Tests updated.
• Documentation added.
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX].
• about-versioning.md updated with experimental features.

[pstibrany]

LGTM from technical point of view, this matches my understanding and the doc I've reviewed before.

[knylander-grafana]

@duricanikolic Thank you for submitting some documentation. I checked out your PR to do a local build. The page isn't showing up in the local build. I'm going to troubleshoot locally and hopefully fix the issue.

Update: Issue is fixed. I did my suggested edits while I had the page checked out. I'll leave comments where I made changes.

[CLAassistant]

All committers have signed the CLA.

[knylander-grafana]

I made some wording changes and marked what I did in the PR. I also found some additional mistaskes that I introduced. I've left them as suggestions so you can see where I made changes.

Please let me know if you have any questions. I'm happy to explain.

[duricanikolic]

I made some wording changes and marked what I did in the PR. I also found some additional mistaskes that I introduced. I've left them as suggestions so you can see where I made changes.

Please let me know if you have any questions. I'm happy to explain.

Thank you very much @knylander-grafana. I have applied your suggestions, and will merge the PR.