Onboarding review flow

[ukutaht]

Changes

Makes the 'review' flow functional in scriptv2 onboarding so that tracker can be viewed/updated after initial installation. Changes are:

• Render the 'review' flow for installationv2 screen
• Adds toggles back into the installation screen
• In installationv2, create tracker script config with form_submissions, outbound_links and file_downloads enabled by default
• Also sync goals immediately when tracker script is created with these options enabled

Remaining work for onboarding:

• Verification tool has to handle scriptv2
• Domain change flow
• Upgrade notices for sites with old script installed
• Tests for new installation screen