docs(vpa): Label `InPlaceOrRecreate` mode as an `alpha feature` in `quick start` guide

This commit adds a dedicated `alpha feature` suffix to `InPlaceOrRecreate`
updateMode to indicate that the option is not available by default and
requires additional setup to enable it.

Also:
- Include reference to the `features.md` documentation to bring
  additional context to the reader and point them to the feature
  details.