Notifications: Evaluate snackbar notifications should they auto dismiss after a few seconds or...?

[jordanCain]

Currently snackbar notifications disappear after a hard coded amount of time, this means some users don't always see the notification so we should determine if we should always wait for a user to dismiss or if we should have a draw for notifications to go to after they've been automatically or manually dismissed

[NakulManchanda]

In zowe desktop we are using notification for all explorers, which resolves this issue

In standalone mode we are going to have new settings page, where user can configure length to small, medium and large.
configuration snackbar notification time is also required for accessibility

[jordanCain]

@NakulManchanda Using predefined notification times is not fully accessible, an other option should also be provided where a user can specify how long they wish a notification to stay along with the option to never auto dismiss

[NakulManchanda]

needs to resolve this:
#487