Build archived state for v1 docs

[sanderson]

This repository will soon be archived and a static snapshot of the documentation will be hosted at a new domain.

• [x] Add a persistent banner about these docs being archived and where they can see the newer docs.
• [x] Delete all content that is still relevant and available on docs.influxdata.com
  • [x] InfluxDB v1.3+
  • [x] Telegraf v1.9+
  • [x] Chronograf v1.6+
  • [x] Kapacitor v1.4+
  • [x] InfluxDB Enterprise v1.5+
  • [x] Platform
• [x] Remove Algolia search functionality
• [ ] Remove sitemap
• [x] Update latest warning block to use latest path and be version agnostic.

[kelseiv]

@sanderson left sitemap in so search engines can still find it.