Add TV screenshots and organize PassepartoutUITests with two test plans
for generating iOS/macOS (Main) and tvOS (TV) screenshots. Revert to the
.attachment destination and use `xcparse` to export the screenshots.
Change iPad screenshots to portrait.
Then autogenerate framed screenshots in two steps:
- Export the UITests screenshots per device (`export.sh`)
- Embed the results in a HTML/CSS template and take snapshots with
Chrome headless (`compose.sh`)
- Repeat for all devices (iPhone, iPad, Mac and Apple TV)
- Save framed screenshots to the `fastlane` screenshots directory