KAT-58: Adding the import for the following page Circulation.dart and the activation of the button <= 30 to navigate to to it.

KAT-55: Adding the import for the following page breathing_frequency_per_minute.dart and the activation of the button JA for the navigation to the next page.

KAT-55new1: All desired changes from KAT-55 were implemented. Creation of the App-Page breathing_frequency_per_minute.dart.

KAt-50: Correted import in main.dart from triage_step1/ambulatory.dart to start_triage_system/ambulatory.dart

KAt-50: Deleted separate directorys: triage_step1, triage_step2/triage_step2_1 and triage_step2/triage_step2_2

KAT-50: Changed all files from Page.dart to page.dart and added separated directory for triage system

KAT-50: Changed 3 state classes of widgets to _AfterOpeningAiwaysState, _AmbulatoryState, _SpontaneousBreathingState

KAT-50: Change page name from MyHomePage3.dart to AfterOpeningAirways.dart and improve design of RaisedButton

KAT-50: Change page name from MyHomePage2.dart to SpontaneousBreathingPresent.dart and improve design of RaisedButton