Support toast messages outside of VueJS

Problem to solve

We currently support toast messages within VueJS applications only. Ideally, we should support toast messages throughout the entire application.

Proposal

Since our toast component uses vue-toasted, the toast messages are dependent on VueJS.

Ideally, we should come up with a solution that is not VueJS dependent.

Documentation

https://design.gitlab.com/components/toasts

What does success look like, and how can we measure that?

Have the ability to display toast messages from anywhere in the application (regardless of whether VueJS is used).