Subscription Confirmation Page

[TylerMatteo]

Create page users will be sent to via a link in the confirmation email.

• Page implements designs seen here.
• Route for new page should be /subscribers/<id>/confirm
• When page is loaded, call endpoint to update user's confirmation custom property to 1
• Text "To modify subscriptions, click here" should link to /subscribers/<id>/subscriptions (page does not exist yet.)
• "Go to Home" button should link to / route.

[TylerMatteo]

Making note of outstanding question on how to get the user's subscriptions into the front end for discussion in sprint planning.

[TylerMatteo]

Note this is depending on #1550 and #1573 to be completed but can be started now.