Add Intro Message

[calebsheridan]

Description

Current swap application uses a different transaction pattern (tip vs gas). We would like users to get more information about the application and its benefits.

On-boarding Message

The on-boarding message should display about the swap component, using an existing UI component (as seen on Governance section). Its content should link users to this blog post describing the application.

Mockup

Note: colors should match application -- not as seen here.