Support truffleruby (graal-native) and truffleruby+graalvm (graal-jdk-based) Ruby interpreters?

[gwiede]

It would be great if frum also offered support for the truffle-based Ruby interpreters, as they're currently the highest-performance Ruby options available. If implementing, please mimic asdf-ruby approach of offering both graal-native and graalvm-jdk-based options (in asdf-ruby presented as truffleruby- and truffleruby+graalvm- respectively). IIRC, the ruby-build tool supports these Ruby options.