Kiosk: add a data-driven System Settings menu

Settings now shows Proclamations, Audio Options, System Settings, System
Logs, and Back. The new SystemSettingsPage groups Email Address, License
Key, WiFi Setup, Time Zone Setup, and Date Format, driven by the pure
settings::systemSettingEntries() list so future entries need one row, not
new menu plumbing. Adds unit tests for the entry list.

tests/test_settings_menu.cpp

@@ -0,0 +1,50 @@
+#include "settings_menu.h"
+#include <gtest/gtest.h>
+#include <set>
+#include <string>
+
+namespace settings = radiantwave::settings;
+
+TEST(SystemSettingsMenuTest, ListsTheSystemSettingsInOrder) {
+    const auto entries = settings::systemSettingEntries();
+    ASSERT_EQ(entries.size(), 5u);
+    EXPECT_EQ(entries[0].label, "Email Address");
+    EXPECT_EQ(entries[0].id, settings::SystemSettingId::EmailAddress);
+    EXPECT_EQ(entries[1].label, "License Key");
+    EXPECT_EQ(entries[1].id, settings::SystemSettingId::LicenseKey);
+    EXPECT_EQ(entries[2].label, "WiFi Setup");
+    EXPECT_EQ(entries[2].id, settings::SystemSettingId::WiFiSetup);
+    EXPECT_EQ(entries[3].label, "Time Zone Setup");
+    EXPECT_EQ(entries[3].id, settings::SystemSettingId::Timezone);
+    EXPECT_EQ(entries[4].label, "Date Format");
+    EXPECT_EQ(entries[4].id, settings::SystemSettingId::DateFormat);
+}
+
+TEST(SystemSettingsMenuTest, LabelsAreNonEmptyAndUnique) {
+    const auto entries = settings::systemSettingEntries();
+    std::set<std::string> labels;
+    std::set<int> ids;
+    for (const auto& entry : entries) {
+        EXPECT_FALSE(entry.label.empty());
+        labels.insert(entry.label);
+        ids.insert(static_cast<int>(entry.id));
+    }
+    EXPECT_EQ(labels.size(), entries.size());
+    EXPECT_EQ(ids.size(), entries.size());
+}
+
+TEST(SystemSettingsMenuTest, EveryEntryMapsToAKnownPage) {
+    for (const auto& entry : settings::systemSettingEntries()) {
+        switch (entry.id) {
+        case settings::SystemSettingId::EmailAddress:
+        case settings::SystemSettingId::LicenseKey:
+        case settings::SystemSettingId::WiFiSetup:
+        case settings::SystemSettingId::Timezone:
+        case settings::SystemSettingId::DateFormat:
+            SUCCEED();
+            break;
+        default:
+            FAIL() << "Unhandled SystemSettingId for label " << entry.label;
+        }
+    }
+}