Add Copy group ID action

Proposal

Add Copy group ID to group dropdown actions

Implementation guide

1. Add ACTION_COPY_ID action to app/assets/javascripts/vue_shared/components/list_actions/constants.js
2. Add action to app/assets/javascripts/vue_shared/components/list_actions/list_actions.vue#L48
3. Add ACTION_COPY_ID action to app/assets/javascripts/vue_shared/components/groups_list/group_list_item_actions.vue

{
  [ACTION_COPY_ID]: {
    text: __('Copy group ID'),
    action: this.onCopyId,
    extraAttrs: {
      'data-clipboard-text': this.group.id
    }
  }
}

onCopyId() {
  this.$toast.show(__('Group ID copied to clipboard.')
}