core: support down migrations to allow reverting to the previous version (#2072)

* core: support down migrations to allow reverting to the previous version

* update schema

* update simplexmq

* rename errors

* remove unused functions

* migration UI, test migration

* update migration UI

* return current migrations in CRVersionInfo

* update simplexmq

* test down migrations

* cleanup ios

* show migrations in log

apps/ios/Shared/Views/UserSettings/DeveloperView.swift

@@ -0,0 +1,50 @@
+//
+//  DeveloperView.swift
+//  SimpleX (iOS)
+//
+//  Created by Evgeny on 26/03/2023.
+//  Copyright © 2023 SimpleX Chat. All rights reserved.
+//
+
+import SwiftUI
+import SimpleXChat
+
+struct DeveloperView: View {
+    @AppStorage(DEFAULT_DEVELOPER_TOOLS) private var developerTools = false
+    @AppStorage(GROUP_DEFAULT_CONFIRM_DB_UPGRADES, store: groupDefaults) private var confirmDatabaseUpgrades = false
+    @Environment(\.colorScheme) var colorScheme
+
+    var body: some View {
+        VStack {
+            List {
+                Section {
+                    NavigationLink {
+                        TerminalView()
+                    } label: {
+                        settingsRow("terminal") { Text("Chat console") }
+                    }
+                    settingsRow("chevron.left.forwardslash.chevron.right") {
+                        Toggle("Show developer options", isOn: $developerTools)
+                    }
+                    settingsRow("internaldrive") {
+                        Toggle("Confirm database upgrades", isOn: $confirmDatabaseUpgrades)
+                    }
+                    ZStack(alignment: .leading) {
+                        Image(colorScheme == .dark ? "github_light" : "github")
+                            .resizable()
+                            .frame(width: 24, height: 24)
+                            .opacity(0.5)
+                        Text("Install [SimpleX Chat for terminal](https://github.com/simplex-chat/simplex-chat)")
+                            .padding(.leading, 36)
+                    }
+                }
+            }
+        }
+    }
+}
+
+struct DeveloperView_Previews: PreviewProvider {
+    static var previews: some View {
+        DeveloperView()
+    }
+}