Banner should say older docs are older versions instead of development versions

[travisn]

The v1.10 and v1.9 pages say that they are a development version of the docs. Let's change this to indicate that they just aren't the latest version, rather than being a "development version" https://rook.io/docs/rook/v1.10/Getting-Started/intro/

[galexrt]

@travisn What about changing the first sentence to This document is for an older release or development version of Rook.?

[travisn]

How about this?

This documentation is not for the latest stable version of Rook.

[galexrt]

Resolved by https://github.com/rook/rook/pull/11808 and the backports for the PR.