Confusing naming of “versioned without staging” extension

[kinglozzer]

Developers can apply versioning without staging (i.e. just version history, no draft/live) by applying the extension using the .versioned-suffixed service name, e.g.:

private static $extensions = [
    Versioned::class . '.versioned'
];

This naming doesn’t really explain what this variant of the extension does. The full versioning mode is suffixed .stagedversioned, which I suspect is where the .versioned suffix came from, but as the default alias for Versioned::class points to .stageversioned, no one ever uses or sees the suffix.

Suggest we adjust the non-staged suffix better explain what this mode is, possible alternatives:

• Versioned::class . '.versioningonly'
• Versioned::class . '.nostages'
• Versioned::class . '.historyonly'

Naming things is always hard, open to suggestions 😄

We can keep the existing service name as an alias, either temporarily to make the CMS5 upgrade slightly easier or just keep it forever (it’s a single line in YAML)