docs: relocate Consul capacity planning page from waf/ to docs/

[krastin]

Description

Do not merge yet, we need a set of redirects first in the tutorial repository first, thank you!

Moving the Consul capacity planning page from WAF/ to docs/ in the shape of an Overview template page.

Testing & Reproduction steps

None

Links

• Consul capacity planning

PR Checklist

• [ ] updated test coverage
• [x] external facing docs updated
• [x] appropriate backport labels added
• [x] not a security concern