Setup app, landing, and session features

...ftpm/xcode/xcshareddata/xcschemes/LandingFeature.xcscheme

...ftpm/xcode/xcshareddata/xcschemes/SessionFeature.xcscheme

...swiftpm/xcode/xcshareddata/xcschemes/example-app.xcscheme

Example/ExampleApp/Package.swift

Example/ExampleApp/Sources/AppFeature/App.swift

Example/ExampleApp/Sources/AppFeature/AppFeature.swift

Example/ExampleApp/Sources/AppFeature/AppView.swift

...le/ExampleApp/Sources/LandingFeature/LandingFeature.swift

Example/ExampleApp/Sources/LandingFeature/LandingView.swift

...le/ExampleApp/Sources/SessionFeature/SessionFeature.swift

Example/ExampleApp/Sources/SessionFeature/SessionView.swift

...le/ExampleApp/Tests/AppFeatureTests/AppFeatureTests.swift

...leApp/Tests/LandingFeatureTests/LandingFeatureTests.swift

...leApp/Tests/SessionFeatureTests/SessionFeatureTests.swift