Remove bootstrap-vue direct package install

This MR removes the bootstrap-vue package installation from gitlab. It replaces direct bootstrap-vue component imports with gitlab-ui wrappers. It also introduces a static assertion that prevents installing bootstrap-vue in GitLab.

Screenshots

With BCarousel	With GlCarousel

How to test (in your local environment)

In https://gitlab.com/gitlab-org/gitlab/blob/master/ee/app/helpers/ee/groups_helper.rb#L86, replace the function implementation with true:

# replace this
def show_discover_group_security?(group)
  !!::Feature.enabled?(:discover_security) &&
    ::Gitlab.com? &&
    !!current_user &&
    current_user.created_at > DateTime.new(2020, 1, 20) &&
    !@group.feature_available?(:security_dashboard) &&
    can?(current_user, :admin_group, @group)
end

# with this
def show_discover_group_security?(group)
  true
end

Open the following route in your GKE environment:

http://localhost:3000/groups/[group-name]/-/security/discover

You should see a UI equal to the one in the screenshots. Use the same approach to test the feature using BCarousel instead of gitlab-ui.