[Getting Started] Default to new add data page

[alexfrancoeur]

The new add data page that includes integrations amongst other cards will be the default experience for adding data to Kibana. We'll want to make sure we make adjustments in two ways.

1. Switch over any entry points from the existing add data tutorials to the new integrations view
   • The interstitial page for self-managed instances
   • The index pattern page
   • Add others
2. When landing in Kibana, whether it's Cloud or self-managed, we want the new add data page to be the first view you see when entering Kibana.

cc: @ryankeairns (we may need design input)

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)