L7 Routing empty state

Overview of issue

• If a user hasn't configured any L7 traffic management stages (routers, splitters, resolvers), show an informational banner at the top explaining why the router and resolver is present by default
• Add tooltips to the default router and resolver cards which appear on mouseover

Desired styling:

Without TCP protocol

NOTE: the images below should have the "Read the documentation" and "Follow the guide" links at the bottom, just like in the "With TCP protocol" image below.

With TCP protocol

Links to include in the informational banner

• Read the documentation:
  • Icon: use same icon as is used on the intention page empty state
  • Link: https://www.consul.io/docs/connect/l7-traffic
• Follow the guide:
  • Icon: use same icon as is used on the intention page empty state
  • Link: https://learn.hashicorp.com/tutorials/consul/service-mesh-traffic-management