Remove references to jaeger-agent

[yurishkuro]

Which problem is this PR solving?

• Part of https://github.com/jaegertracing/jaeger/issues/4739

Description of the changes

• Remove references to jaeger-agent everywhere except FAQ and Operator
• Operator page needs to be cleaned-up separately, perhaps it needs changes in the operator to support OTEL Collector as the agent

How was this change tested?

• CI

[netlify[bot]]

✅ Deploy Preview for romantic-neumann-1959d7 ready!

Name	Link
🔨 Latest commit	4329486bb1534074a258caaee5d928aa3ac98a73
🔍 Latest deploy log	https://app.netlify.com/sites/romantic-neumann-1959d7/deploys/670dc969a979ba0008726843
😎 Deploy Preview	https://deploy-preview-757--romantic-neumann-1959d7.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.