feat(user): migrate color scheme settings to persistance in db

src/views/user/settings/General.vue

@@ -111,7 +111,7 @@
 					{{ $t('user.settings.appearance.title') }}
 				</span>
 				<div class="select ml-2">
-					<select v-model="activeColorSchemeSetting">
+					<select v-model="settings.frontendSettings.colorSchema">
 						<!-- TODO: use the Vikunja logo in color scheme as option buttons -->
 						<option v-for="(title, schemeId) in colorSchemeSettings" :key="schemeId" :value="schemeId">
 							{{ title }}
@@ -161,10 +161,8 @@ import ProjectSearch from '@/components/tasks/partials/projectSearch.vue'
 import {SUPPORTED_LOCALES} from '@/i18n'
 import {playSoundWhenDoneKey, playPopSound} from '@/helpers/playPop'
 import {createRandomID} from '@/helpers/randomId'
-import {success} from '@/message'
 import {AuthenticatedHTTPFactory} from '@/helpers/fetcher'
 
-import {useColorScheme} from '@/composables/useColorScheme'
 import {useTitle} from '@/composables/useTitle'
 
 import {useProjectStore} from '@/stores/projects'
@@ -176,30 +174,11 @@ useTitle(() => `${t('user.settings.general.title')} - ${t('user.settings.title')
 
 const DEFAULT_PROJECT_ID = 0
 
-function useColorSchemeSetting() {
-	const {t} = useI18n({useScope: 'global'})
-	const colorSchemeSettings = computed(() => ({
-		light: t('user.settings.appearance.colorScheme.light'),
-		auto: t('user.settings.appearance.colorScheme.system'),
-		dark: t('user.settings.appearance.colorScheme.dark'),
-	}))
-
-	const {store} = useColorScheme()
-	watch(store, (schemeId) => {
-		success({
-			message: t('user.settings.appearance.setSuccess', {
-				colorScheme: colorSchemeSettings.value[schemeId],
-			}),
-		})
-	})
-
-	return {
-		colorSchemeSettings,
-		activeColorSchemeSetting: store,
-	}
-}
-
-const {colorSchemeSettings, activeColorSchemeSetting} = useColorSchemeSetting()
+const colorSchemeSettings = computed(() => ({
+	light: t('user.settings.appearance.colorScheme.light'),
+	auto: t('user.settings.appearance.colorScheme.system'),
+	dark: t('user.settings.appearance.colorScheme.dark'),
+}))
 
 function useAvailableTimezones() {
 	const availableTimezones = ref([])
@@ -222,7 +201,7 @@ const settings = ref<IUserSettings>({
 		// Sub objects get exported as read only as well, so we need to 
 		// explicitly spread the object here to allow modification
 		...authStore.settings.frontendSettings,
-	}
+	},
 })
 const id = ref(createRandomID())
 const availableLanguageOptions = ref(