Major frontend code cleanup (#452)

Many large changes, including:
- TypeScript enums are now string unions throughout
- Strong type-checking throughout the TS and Vue codebase
- Vue component props now all specify `as PropType<...>`
- Usage of annotated return types on all functions
- Sorting of JS import statements
- Explicit usage of Vue bind attribute function call arguments (`@click="foo"` is now `@click=(e) => foo(e)`)
- Much improved code quality related to the color picker
- Consistent camelCase Vue bind and v-model attributes
- Consistent Vue HTML attribute strings with single quotes
- Bug fix and clarity improvement with incorrect hint class parameters
- Empty Vue component objects like `props: {}` and `components: {}` removed

frontend/src/components/widgets/inputs/RadioInput.vue

@@ -85,7 +85,7 @@ export type RadioEntries = RadioEntryData[];
 export default defineComponent({
 	props: {
 		entries: { type: Array as PropType<RadioEntries>, required: true },
-		selectedIndex: { type: Number, required: true },
+		selectedIndex: { type: Number as PropType<number>, required: true },
 	},
 	methods: {
 		handleEntryClick(menuEntry: RadioEntryData) {