docs: readability tweaks to "Install" page

[StackScribe]

DO NOT MERGE!

Summary

Improve the readability of the Install page (revised for umbrella charts). We did a quick merge of the basic material, knowing that it needed to be tweaked a bit.

While this PR was written, Mo created an abbreviated document that is much more appropriate. This version is going to be used for some usability testing but should not be merged. Instead, the plan is for me to create a separate "Installation tips and tricks" page that includes the content from this page that is not in the abbreviated installation doc. When that is done, this PR will be closed.

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• [n/a] I regenerated the auto-generated docs for Helm and the CRD documentation (if applicable)
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[odubajDT]

Please fix the failing html test

HTML tests fixed

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

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[StackScribe]

This PR is no longer relevant -- the useful bits were put in other PRs and I am closing this.