Drop versioned documentation

[ciscoo]

The documentation has changed little since it was first created. The core content has largely remained the same with additions here and there. The main notable change was dropping the extension in favor of creating tasks directly using the tool options. But other than that, not much.

Versionless documentation also simplifies publication since GitHub Actions can handle publication rather than the Gradle plugin used today.

A proper changelog and/or release notes (#107) is important for this as well.