Add new duo pro discover page

What does this MR do and why?

What

Add new duo pro discover page

• Adds new discover page for duo pro
• Adds requirements from section 1 of MVC design (header, video, & tracking) other than expired trial requirements:
  • User can access the Duo Pro discover page by clicking the learn about features link in the Duo Pro active trial widget
  • Clicking on the Duo Pro active trial widget itself directs the user to the Duo Pro trial discover page
  • Within the Duo Pro trial discover page: Clicking on the Buy now button directs the user to the GitLab Duo Pro tab of the namespace's /usage_quotas page
  • Within the Duo Pro trial discover page: Clicking on the Contact sales button opens the Duo Pro hand-raise PQL modal
  • Clicking the video screenshot in the upper righthand corner of the page opens a new tab and directs the user to the vimeo link
  • Event tracking is implemented

Why

We've recently released our MVC of Duo Pro Trials for Gitlab.com, Self-Managed, and Dedicated. The MVC lacks an in-trial onboarding experience and ongoing active trial UX (this is being addressed in https://gitlab.com/gitlab-org/gitlab/-/issues/452107). With the early success of the Trial Discover Page experiment, we'd like to explore the possibility of using the same structure and design layout for a dedicated Duo Pro Trial page that continuously promotes the value of Duo Pro during the trial period and after the trial is over.

from https://gitlab.com/gitlab-org/gitlab/-/issues/452515#note_1904706287

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

New

How to set up and validate locally

• Setup gdk to simulate SaaS - https://docs.gitlab.com/ee/development/ee_features.html#simulate-a-saas-instance and restart GDK
• Sign out. Sign up and create new group during sign up or afterwards.

bin/rails c

Feature.enable(:duo_pro_trials)
GitlabSubscriptions::AddOn.find_or_create_by(name: 'code_suggestions', description: GitlabSubscriptions::AddOn.descriptions[:code_suggestions])
GitlabSubscription.last.update(trial: true, trial_starts_on: 45.days.ago, trial_ends_on: 15.days.ago)
GitlabSubscriptions::AddOnPurchase.create(subscription_add_on_id: GitlabSubscriptions::AddOn.find_by(name: 'code_suggestions').id, namespace: Group.last, started_at: 60.days.ago, expires_on: Date.today, trial: true, quantity: 1, purchase_xid: '1')

• Visit group page. Active trial widget should appear and either clicking the widget itself, or the Learn about features within the widget popover should direct to the discover duo page

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/462649