[Guided onboarding] Onboarding landing page improvements

[alisonelizabeth]

This work is continuation of #134245.

For 8.6, we will be building a guided onboarding experience for each solution. The /app/home#/getting_started landing page implemented in 8.4 will serve as the starting point to kick off a particular guide, and we will need to update this page accordingly.

Changes include:

• A new "View guide" button per card
• Support for the button to initiate a guide OR redirect to a page if no guide is available
• A tag at the top of the card to categorize the guide type
• Add any new cards necessary

Mockups

Current UX:

Proposed:

Questions/Dependencies

• What are the finalized guides/workflows that we will deliver for 8.6 and display on this page? For each guide, we need to know if it will be supported by the full guided workflow, or will simply redirect the user to a particular page.
• We will need the finalized copy for each guide

[elasticmachine]

Pinging @elastic/platform-onboarding (Team:Journey/Onboarding)