bootstrap-vue-next: some problems with BToastPlugin

1. BToastPlugin and ‘useToast’ not found.

However, you can do it with the following import

// ToastPlugin=BToastPlugin
// but 'useToast' not found.
import BootstrapVue3, {ToastPlugin} from 'bootstrap-vue-3'

or

import BToastPlugin, {useToast} from 'bootstrap-vue-3/src/components/BToast/plugin'

1. toaster hides in fixed-top class

toaster z-index: 11 fixed-top z-index: 1030 see Bootstrap z-index