Update use case, registration and login screens.

Remove "Custom server" button from use case screen.
Remove matrix.org description.
Add username availability to registration screen.

RiotSwiftUI/Modules/Onboarding/UseCase/Coordinator/OnboardingUseCaseSelectionCoordinator.swift

@@ -57,9 +57,7 @@ final class OnboardingUseCaseSelectionCoordinator: Coordinator, Presentable {
             MXLog.debug("[OnboardingUseCaseSelectionCoordinator] OnboardingUseCaseViewModel did complete with result: \(result).")
             
             // Show a loading indicator which can be dismissed externally by calling `stop`.
-            if result != .customServer {
-                self.startLoading()
-            }
+            self.startLoading()
             self.completion?(result)
         }
     }

RiotSwiftUI/Modules/Onboarding/UseCase/OnboardingUseCaseModels.swift

@@ -29,7 +29,6 @@ enum OnboardingUseCaseViewModelResult {
     case workMessaging
     case communityMessaging
     case skipped
-    case customServer
 }
 
 // MARK: View

RiotSwiftUI/Modules/Onboarding/UseCase/View/OnboardingUseCaseSelectionScreen.swift

@@ -29,6 +29,23 @@ struct OnboardingUseCaseSelectionScreen: View {
     
     @ObservedObject var viewModel: OnboardingUseCaseViewModel.Context
     
+    var body: some View {
+        ScrollView {
+            VStack(spacing: 0) {
+                titleContent
+                    .padding(.bottom, 36)
+                
+                useCaseButtons
+            }
+            .readableFrame()
+            .padding(.top, OnboardingMetrics.topPaddingToNavigationBar)
+            .padding(.bottom, 8)
+            .padding(.horizontal, 16)
+        }
+        .background(theme.colors.background.ignoresSafeArea())
+        .accentColor(theme.colors.accent)
+    }
+    
     /// The screen's title and instructions.
     var titleContent: some View {
         VStack(spacing: 8) {
@@ -76,47 +93,6 @@ struct OnboardingUseCaseSelectionScreen: View {
             .padding(.top, 8)
         }
     }
-    
-    /// A footer showing a button to connect to a server.
-    var serverFooter: some View {
-        VStack(spacing: 14) {
-            Text(VectorL10n.onboardingUseCaseExistingServerMessage)
-                .font(theme.fonts.subheadline)
-                .multilineTextAlignment(.center)
-                .foregroundColor(theme.colors.tertiaryContent)
-            
-            Button { viewModel.send(viewAction: .answer(.customServer)) } label: {
-                Text(VectorL10n.onboardingUseCaseExistingServerButton)
-                    .font(theme.fonts.body)
-            }
-        }
-    }
-    
-    var body: some View {
-        GeometryReader { geometry in
-            VStack {
-                ScrollView {
-                    VStack(spacing: 0) {
-                        titleContent
-                            .padding(.bottom, 36)
-                        
-                        useCaseButtons
-                    }
-                    .readableFrame()
-                    .padding(.top, OnboardingMetrics.topPaddingToNavigationBar)
-                    .padding(.bottom, 8)
-                    .padding(.horizontal, 16)
-                }
-                
-                serverFooter
-                    .padding(.horizontal, 16)
-                    .padding(.top, 8)
-                    .padding(.bottom, geometry.safeAreaInsets.bottom > 0 ? 20 : 36)
-            }
-        }
-        .background(theme.colors.background.ignoresSafeArea())
-        .accentColor(theme.colors.accent)
-    }
 }
 
 // MARK: - Previews