Adds logic for determining active LTS branches for a given release configuration. The active LTS branches can be determined by querying NPM and matching dist tags against a specific pattern. i.e. `v{major}-lts`. This logic will be useful for the release tool that supports publishing of active LTS version branches. PR Close #38656
Versioning for the Angular organization
The folder contains common tooling needed for implementing the versioning as proposed by this design document. Primary tooling is the determination of active release trains.