* Add v-item-group / v-item / groupable compositions
* Add support for multiple prop
* Handle internal selection, prepare for custom v-model
* Support v-model in item-group
* Add docs
* Register new components
* Fix typing of and add tests for array equal util
* Move is-empty to util
* Base all internal state on index / value instead of id
* Cleanup usage of groupableParent
* Add support for max option
* Add support for mandatory
* Add docs / cleanup code
* Add full test coverage for groupable compositions
* Add tests for v-item / v-item-group