update for release branch or LTS and conform to the Zephyr example application

[cfriedt]

The Zephyr example application is the authority for how Zephyr modules should be organized.

Additionally, with the release of v2.7.0 (LTS2), we should change which rev we point to.

It would also make sense to adopt a similar tagging convention for tagged releases.

E.g. update west.yml to point at v2.7.0, tag v2.7.0, and and then update west.yml to point at main

When v2.7.1 is tagged, similarly, we should update.

[cfriedt]

Probably will not be upgradeable on v2.7 branch due to additional requirements that will not be backported.

Updating this issue to reflect that we should be pinning to releases (ideally LTS)