make README.md easier to parse

[mininmobile]

• separate "getting started" from deployment instructions for laypeople who simply want to use cinny
• break up deployment instructions so it is easier to interpret
• remove commands for the docker pulls, as they are on the respective repositories
• explain what hash routing is, link to all webserver config examples (assuming add example caddyfile #2227 is merged too)
• bold pgp key dropdown to make it stand out
• make the recommendation to use nvm a spiffy tip alert

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[mininmobile]

I have read the CLA Document and I hereby sign the CLA ✅

[kfiven]

The changes looks good @mininmobile , could you please comment recheck so that all checks can pass?

[mininmobile]

recheck

[github-actions]

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