Update README.md

[slrslr]

Removing duplicity which does not belong to the installation section.

[MudDev]

Thanks @slrslr — your duplication observation is correct; almost all of the deleted Quick Start content is genuinely repeated in Usage below.

Closing this in favor of #45, which keeps your scope-reduction and adds two small follow-ups:

1. Preserves the "only you can modify" ownership detail (deleted step 3) by folding it into the Site Management "Create new site" bullet — that was the one piece of information from the walkthrough not duplicated elsewhere.
2. Drops the now-stale #creating-your-first-site anchor from the Quick Start jump-to block we added in docs(readme): add Quick Start jump block, label OS-specific install sections #36, which would otherwise become a broken link after your removal.

You're credited in the commit and PR description. Thanks again for the steady cleanup work on the README.